Oh, oh! I know this one.
Apple's devices are extremely closed. This is antithetical to the spirit of personal computing. But this is only one component: what ultimately pushes Apple to generate an anti-Apple crowd is the combination of them being a closed platform, them using every dirty trick in the book to suck users into their closed ecosystem, and them being extremely successful at it.
Want to make an iOS app? Buy a Mac. No, not an old Mac, a new one.
Want to send proper messages to an iPhone user? Get an iPhone. Or convince them to install Signal. (I'll wait! LOL.)
Want to make a video call to an iPhone user? Get an iPhone. (Or ask them to install Duo, haha!)
Want to install Mac OS? Buy our hardware.
None of this would matter so much if we were talking about coffee makers. But we're talking about personal computing, a very central component of our nerd lives. If you're a youngster you're probably happy with occasional hardware replacement and messes of dongles, but for many of us our computing experiences are rooted in opening up the box and switching the guts around, or booting different software on the box, and we don't especially appreciate having to constantly battle the hardware vendor to make this happen.
Apple products seem to be very high-quality. But that's not really the point.