People who do stuff they shouldn’t, like using non-recommended kernel or driver versions or replace critical system components from AUR, then blame it on the distro when stuff breaks.
People who don’t understand how AUR works and think that Manjaro holding back binary packages for a couple of weeks has any effect on AUR (which is built from source…)
People who can’t get over the times when they didn’t renew their certs or when they accidentally DDoS’ed the AUR. It doesn’t matter if the distro is good or not. Those instances of carelessness should be held against it forever.
People who can’t stand the fact it’s a commercial distro.
People who can’t stand the thought of any Arch-based distro that dares to do anything different from Arch (other than make the install easier, that one seems to be acceptable for some reason; but there are more extreme people who dislike that too).