Before we begin, I would like to say there is a difference between a fan and a fanboy. So if you are a fan of Marvel, DC, or both, do not fret. I am not attacking you.
Fanboys, they spend their spare time(which is likely all of their time) defending a company, person, product, etc, on message boards and threads, while criticizing a similiar yet different company, person, product, etc. You already know this though, and you recognize the proccess as trolling.
Apparently, DC fanboys as of late, are claiming that their is a double standard between the two. Marvel fanboys(and regular fans as well) do not complain about anything Marvel does, but will criticize DC for any decision, even similar ones to Marvel's. Whether it's Marvel's costumes vs DC's, Marvel's casting vs DC's, characters faithfulness to the source in Marvel and DC films, the use of realism, or even the new one, criticizing the studios' choice of wanting a female director at the helm of a female lead CBM.
Similar things are said about castings, and again I can say there is less complaints on Marvel's side, but to Marvel fans and critics, their casting has been spot on. Even the ones that seem like they weren't good choices in the past, has surprised the fans and critics. After seven years of this, people are more willing to trust Marvel when it comes to casting, but as I said, it does not stop the complaining. It's not hypocrisy; it's like saying it's hypocritical for someone to trust their money with a finiancial advisor vs a man/woman who lost their life savings in a casino(not saying DC is that bad, I'm not saying their bad at all, just that the DCCU is in it's infancy and have yet to garner the trust that the MCU has). It's actually a double standard to force people to have the same amount of trust in someone who hasn't earned it.
Not to be lazy, but to avoid writing and you reading the same argument three more times in this article, I will stop at that last point.
I will not argue with anyone who says that Marvel trolling has been more frequent than DC trolling, but in the end, there is not a double standard. Trolls, and Fanboys are what they are, and they do the same thing no matter what they choose to defend and criticize. Marvel having more fanboys is a result of Marvel starting their very successful cinematic universe back in 2008, while the DCCU just sprung into life in 2013. Of course there was more balance during Nolan's Batman trilogy, but not every Nolanite was a DC fanboy, so now that his trilogy is being over shadowed by the upcoming slew of CBMs the Nolanites are beginning to fade. Marvel fanboys are hypocritical though, and do follow Marvel blindly and criticizing DC with every step they make, but DC fanboys are the same. A double standard do exist, but not in the way DC fanboys claim.