That's not Marvel vs. DC. It's the general destructive mentality that's infected all levels of our society from fandom to government. A subset of disgruntled, entitled people who feel their comfortable white male privilege is under attack are reacting by attacking back, conspiring to tear down their rivals by any dishonest means necessary. We saw it a few years ago with the Sad and Rabid Puppies gaming the Hugo Awards with "voting slates" to try to make sure their approved, far-right-skewing candidates won or just to childishly sabotage the awards by nominating porn stories, and we see it now with disgruntled fanboys gaming Rotten Tomatoes in a similar way to try to artificially shrink the scores of movies that don't fit their preferred politics. Marvel vs. DC is just their excuse -- it's no coincidence that they're targeting an Afrocentric movie. I mean, they're hosted by, and openly emulating, the group that claimed credit for rigging the Last Jedi score, and that group was overtly "Alt-Right" (i.e. Neo-Nazi) in its politics and condemned TLJ for having heroes who weren't all white men. This is about something far, far darker and more dangerous than a rivalry between superhero franchises. This is driven by the very thing that all comics superheroes have been fighting against since the beginning of the genre.