Fandom Problem #14,907:
Reboots.
Now, not for the reason you probably first thought. My gripe comes from the old fans. Those who refuse to accept that the hard, let's start from the beginning reboot isn't exactly like the original. Those who will complain about every little thing. Those who once stated that there were flaws in the original suddenly act like those flaws never existed and the original was the best thing ever. Those who will watch the reboot and then hiss and snarl about every conceivable thing. Those who don't exactly attack new fans but will constantly post about how terrible the new reboot is and how no one should like this 'garbage'.
You know the exact type of fan I'm talking about.
Like, I get it. It's extremely hard watching that thing you adored during childhood be turned into a new cash-grab. God, there are countless examples of this. I'm not talking about that specifically, however. I'm talking about the behavior of the older fans and fandoms.
I know you don't want to hear this - reboots aren't meant for old fans. They're for pulling in a new generation of fans. Yes, majority are cash grabs or to sell toys. Making shows specifically to sell new dolls or toys isn't a new thing, though.
Maybe instead of shitting all over the thing the newer generation takes interest in, guide them toward the original? Constantly shouting that the new reboot is awful and garbage, and whatever other insult you can find doesn't help in the slightest. The new fans will take a look at your posts and decide to stay away from that toxic fandom.
Stop attacking new fans. You're allowed to outright despise the reboot, but others are also allowed to like the thing, and they should be allowed to make content for that thing without having to deal with frustrated old fans. A hard pill to swallow for some, I know.