In my experience those who hate another platform do it because of their own misconceptions.
People hate Macs because they perceive Apple computers as too expensive, but a good chunk of those people are comparing a Mac to their 500€ plastic laptop, who still ships with a mechanical drive, a unusable trackpad, low-res screen and 3-4 hours battery life; the same goes for iDevices, of course the iPhone and the iPad are expensive if you're comparing them to a mid range phone or tablet.
Others hate on other platforms because of the learning curve, and I understand that, and I think this is in part due Apple's misleading marketing; every platform is easy to use once you've learned it, but every OS made by Apple does have a learning curve, it surely isn't as steep as Arch's of course, but it's there, and people who are used to perform basic tasks with their devices will find the curve too steep - I'm not tech illiterate, but whenever I need to take a screenshot on my Mac, I still end up googling the key combination -, so I think some people tried to use a Apple device thinking it was a breeze to use, then faced the learning curve, abandoned the platform and remained bitter towards Apple, it's the case of a friend of my uncle's, he bought everything from Apple, then the first time he couldn't open a file, instead of looking for a solution, he just sold everything, all of this in a matter of one week.
I used to hate everything Apple, I perceived Apple's products as overpriced, until I got a Samsung Galaxy S8 Plus and installed the first OS upgrade, in a matter of minutes the phone became noticeably slower, the touch input became less precise and responsive, and the battery life got cut; in the meanwhile two colleagues of mine had the iPhone 7, their phones were older than mine, running the latest OS and still flying, I asked them to let me try their phones, and then sold the S8 Plus and got an iPhone 8, then the 11 when it came out and I am not planning on buying an Android phone for the foreseeable future.
When I got my Mac the learning curve was there, as it was there when I decided to use Linux (Ubuntu), as it was there when I got Windows 10; one thing some people fail to realize is that using a different platform is a little bit like speaking in a foreign language, if you want to master a foreign language grammar and vocabulary are not enough, you need to be able to think in a different way, the same goes for operating systems. Now that I'm accustomed to macOS I prefer it over Windows and Linux, even though I still use all three of them - Linux is more of a pleasant hobby for me, though -.
Then of course you have the herd mentality, on the Internet it's very easy to develop it and being engulfed by it, on many websites or subreddits, if you don't conform then you'll be downvoted to hell, or even outright banned, for example once on reddit I was attacked because I said that I prefer Apple Music over Spotify, subjectively Apple Music sounded better to me and Apple Music's suggestion are more on point than Spotify's, I was told I was wrong, because, according to that user, Spotify used better encoding, so it was not possible for me to find Apple Music as the better sounding option, luckily I never visited a gaming forum and told everyone that I chose the Xbox over the PlayStation because I prefer the shape of the Xbox controller or that I consider Red Dead Redemption 2 as my worst game purchase...
So, if someone is reasonable in their hate towards a corporation, and there are many reasonable arguments to hate a whole slew of corporations, I like to have a conversation with them, even a lengthy conversation even if they're just strangers on the Internet, but if someone is hating just because then I'll just move on.