On both sides it's the Marvel Vs DC people doing this the most, or at least they do it to the one they don't like. As someone who likes all the movies but a very few (none in either current Cinematic Universe) I feel I have a more unbiased perception.
First off since Guardians of the Galaxy came out it's like people have been judging the entire MCU based on that film, and really a flanderized version of it, as if nothing was taken seriously and it had no depth, which is clearly wrong. No other MCU film is as comedic, the amount of humor in them isn't really much more then you get in the DC films, DC just doesn't put the jokes in the trailers as much.
And the people praising what Marvel does over DC, go on about DC being ashamed of their properties because they seemingly tone things down to make them more realistic. But the MCU films have also watered things down to make them less comicbooky, Zola wasn't actually a living Brain like Krang, the Guardians of the Galaxy had all the most Superpowered members of it's team removed. and the Collector was completely weakened. Plenty in the MCU has felt Nolanized, not to mention Mandarin.
And of course the current DCCU only has one movie we've seen. And the way I see it every glimpse we've seen of Batman V Superman and Suicide Squad has undermined the notion that DC is afraid to embrace the flamboyant aspects of their Universe. It's funny actually, all the talk about how DC was running their movies by being to realistic, and now the SS pics come out and everyone is whining how unrealistic it looks. They're clearly fully embracing the Magick of their universe way faster then it's taken Marvel. And it's clear that Snyder was being held back from his more stylish style for MOS and isn't anymore for BvS.
I've even seen some claim that Ironically DC is less dark and serious then Marvel in the Comics and so find DC taking the darker rout for Movies a rejection of everything DC stood for.
That depends on what period you're talking about, if you're talking about the Silver and to a lesser extent Bronze age then yes, that's true. The times when DC was loosing to Marvel in sales.
But the DC Comics I fell in love with as a child of the 90s and early 2000s were very dark. Even the ones that had Superman. Identity Crisis, OMAC Project, Infinite Crisis, the Teen Titans under both Wolfman/Perez and Geof Johns. Batman getting his back broken, Superman dying and coming back, Hal going crazy, these are the stories that made me a DC fanatic. And for Batman stuff like Bruce Wayne Murderer/Fugitive and War Games, and Under the Red Hood. In the 90s was when Marvel was massively loosing to DC in sales.
The MCU does have plenty of darkness and seriousness. And MOS had plenty of humor.
I've also seen haters of the current DC Cinematic Universe saying DC is doing it right on TV, and then putting Arrow and The Flash together just because they're technically in the same universe. The Flash has been great, fantastic, marvelous. Arrow however to me has been doing exactly what the DC Cinematic Universe is being falsely accused of.
If you're gonna refute that assessment with "Arrow included the Lazuarus pit for Ra's and the movies didn't". Those movies aren't in this Cinematic Universe, that's the problem, Nolan's style that was perfect for Batman but not so ideal for others is being assumed to still rule the upcoming DC films. The things about MOS that were accused of coming from Nolan are clearly gone from Batman V Superman based on what we've seen so far. And I don't think those things were actually Nolan's fault anyway, Nolan's movies certainly didn't desaturate their colors. Of course the "Man of Steel in Color" video on Youtube is a fraud, MOS wasn't that desaturated as they claimed there. But I do wish it had been brighter and it looks like BvS will be.
Having the Lazurus pit doesn't help Arrow's take on Ra's and the League of Assasins since they removed most of his exotic charisma, and has all the League members wearing the same boring looking costume. And they removed his Eco Terrorist motivation and have him pretty much being Evil simply to be Evil.
Arrow had a strict rule against Super Powers until sharing a continuity with The Flash was thrust upon them. Their Suicide Squad contained none of the truly Flamboyant members. They've pretty much treated Oliver as if he were Batman, Oliver is not such a grim anti-social character in the Comics. And they refuse to give Black Canary her authentic costume with the Iconic Fishnets, instead just making her look like a slighter more prudish Catwoman. And of course they are taking their sweet time letting Ray Palmer shrink.
The recent SS pics show the Cinematic Universe is much more willing to embrace truly Comic Book like Costumes. Harley Quinn will have more then one costume in the film, I too am not fond of the New52 based one in the first pics we saw, Arkham City had the ideal Harley costume to me. But regardless it is from the comics. And their look for Enchantress is less realistic then any form I've seen her have in the comics.
And sometimes the "toned down" version of the character, is more like how they originally were before later writers started exaggerating them. That's why I love this Killer Cros look, I'm sick of the overdone Killer Croc we see in the Arkham games. On the other hand, Echantress's look reminds me of what I don't like about Poison Ivy in the Arkham games.
What really bums me out about the BrosWatchPLLToo duo being so firmly on this DCCU hating bandwagon, is that I know they like me care a great deal about women being treated better in genre fiction. The DC has had a horrible track record with this in the Comic all through the New52 and even a little before. But in other media right now, especially with movies they are doing far better then Marvel.
Marvel continues to refuse to include Black Widow and Gamorra in the merchandising, while DC is making a new line for young Girls, I just hope it corresponds with better female representation in their main marketing lines.
The MCU is taking till Phase 3.5 to give us a female lead Solo film, and we know from leaked emails their CEO has no confidence in female lead Superhero films. With DC we'll have Wonder Woman before then even though they got started later. WW will be the 4th film total, 3rd after it was confirmed we're getting a universe, and before the first JL film. Gail Simon said someone she trusts told her WW will be the best part of BvS, and I always knew Gadot would do awesomely.
Marvel kept the full Smurfette principle for it's first two team films and then just now upgraded to 2 women in a team of 9. Suicide Squad will unfortunately have twice as many men as women, but at least DC has more then 2 women on the team right from the start.
And they aren't all White. Age of Ultron featured all of the core 3's Black Friends in small roles, how diverse of them.
I have my concerns with both DC and Marvel's upcoming plans, but I remain excited for both.