Here's my take on it coming from a life long PC user. I only made the switch in November of 2012 after having used MS DOS since 5.0 and Windows 3.1, and a Commodore 64 before that.
Like many school children from my generation, our first introduction to Macs were at school in a mandatory computer class. I think I must have been in grade 2 or 3 when they were introduced (c.1991-1993). At the time, having a home PC wasn't very common, and it was even rarer that someone had a Mac. I think maybe 1 kid had a mac in my class at home, and even then just a handful had PCs. I recall being one of the only few kids who knew my way around a computer, other than Kyle, the Mac kid.
At that age, the biggest use for the PC was gaming. Games, games games games games, and that would remain the focus for many years to come. Yet, as a grade 2/3 child, when we got to using Macs in class, we learned how to type, do spreadsheets and word process and use print shop pro (thanks Ms. Osborne!). We even fiddled around with Hypercards, and if we had spare time, we could play Sim City, Cross Country Canada, Where in the world is Carmen Sandiego, or Spelunk, Math Blaster or something.
From my perspective at the time, these games weren't that great. I could play Sim City at home, in colour, and the same for Carmen Sandiego. On top of that, I had to have a disk to save my work and games. Not quite the same as just being able to save it locally on a hard disk. Of course in retrospect I understand why this was the case.
As a kid the reasoning I had was that Apple computers were meant to be used at school, and PCs were meant to be used at home. I can distinctly recall getting excited that we would be able to use PCs at school upon entering secondary school, though our we did have some Macs in addition to PCs.
Anyways, it basically boiled down to: You can game on a PC, you can't on a Mac. I recall at one point in grade 11, one of my friends (who had always been in love with Macs) getting excited about getting the new iMac at the time. My friends were kind of putting him down because they were proclaiming what a piece of junk it was without having ever used it. I recall saying at the time, that they have their uses for graphics and such, (but my friend doesn't seem to recall me partially trying to defend him).
Basically for teenagers in the early millennium, Macs just weren't suitable for their gaming needs.
My older brother who worked in game development at the time also made a point of mentioning to me which games were graphically done on Macs and such, so I kind saw the other side of the coin as well at the time. On the flip side, we always used to make fun of Windows 95/98/98SE/ME (2000 was the only good one) even though we used those OSes day in and day out.
Fast forward to more modern times, I think a lot of the hate stems from the publicity that Jobs got, and the fact that some people absolutely detested his personality. That counts for a lot.
People that build PCs as enthusiast love to have control over their systems. Apple doesn't want that, so it is not difficult to see where tensions can arise. Furthermore, people make the claim "I can build a comparable system or better" for less argument, or they just also really like blue LEDs all over their tower. I'll admit to being part of the latter, because I always loved gaming. That being said, while there are some nice industrial designs out there for gaming towers, but a large majority a lot of them look tacky, and really plasticky.
Yet another point that I think sticks with hardware enthusiasts, is that there exists a segment of Apple fans that know absolutely nothing about hardware and components, and yet talk as if they do. This also bothers me.
Anyways to each their own. While I am equally comfortable in either platform, I still prefer Macs nowadays because I just don't game like I used to.
I'm in my 30's now and only got my first Mac in 2010. I've wasted far too much of my life on Windows.
