It might have to do with Marvel absolutely hitting it out of the park w/ few missteps along the way (animation excluded of course).
The MCU movies have all been increasingly beastly in the box office.
MCU TV had to crawl before it got up and started running. and now there is even more on the way.
The comics have been wisely pushed alongside the movies and they continue to push diversity in characters through gender/race and relatability.
TV Animation... well, EMH was doing great, but they killed that and replaced it with 2 or 3 other shows that I've heard nothing good about (Avengers, Hulk Smash & something else?), but haven't watched myself. and Ultimate Spider-man could definitely be better.
DVD Animation.... well, all that madhouse anime stuff... I'm not really sure what to say about it. I don't think Anime fits the Marvel style. I think they need to bring it in-house and let the Disney animators form a new studio just for them.
DC on the other hand
DVD Animation. 2nd to none as far as comic animation has been for quite some years now.
DC Movies... well, we have some MoS, TDK trilogy, Green Lantern, and then a bunch of other movies people probably didn't even know were DC properties, regardless of a DC logo infront* of it (Watchmen, Constantine, V for Vendetta, etc etc etc).
DC TV we got the awesome Arrow, and soon we have The Flash (on this little watched network called The CW). ontop of that we will also have Gotham, iZombie, and Constantine coming up.
As far as mass appeal to the general public, all DC has is a mediocre Superman movie, that followed a fairly bad Superman movie. A horrible Green Lantern movie and the Dark and Gritty Batman Trilogy that has nothing to do with everything else happening at WB/DC right now. They also have a dull logo that no one remembers seeing.
* Marvel has a great animated Logo that people get excited about when they see. They also remember seeing it and it makes them pay a little more attention to whatever is on screen once they recognize that comic flipping logo. DC really needs to get something a little more catchy than just putting DC up on the screen.
point being as far as MASS GENERAL POPULACE is concerned, Marvel is on FIRE. They have delivered for the most part on every "Marvel Studios" tagged release and faith and trust has been built that they will deliver on the next one.
DC has tripped and bruised their knees on GL, then studder stepped with MoS. That trust and confidence with DC building a universe has not yet been established. All that is seen is that Marvel connected a bunch of movies into a major event that broke BO records, and now DC is trying to do the same thing. Their approach has appeared to be more reactionary than inspired, so they are getting criticized a little more fiercely than they want.
Once these next 2 movies come out and prove themselves to be more than a quick attempt at copying Marvel, and an actual good use of the IP's in play, then maybe most of the more vocal haters will STFU. But they haven't earned anything yet.