I don't think any opinion in this topic can really be wrong since it is all pretty much subjective. That said
I'd much rather use OS X than god-awful Windows
I've always classed OSX as a PC. Not really sure why other don't. You can play PC games on it and quite well for the most part. I enjoyed playing on macs recently.
I'd hate to play online with "PC Master Race" kids. This is probably the biggest, as I find most vocal proponents for PC gaming to be insufferable.
Now this is hilarious to me, because a key motivator for moving away from console gaming was my experience with online with the 360.
In every game, I found myself being stuck with the most obnoxious & churlish of people from kids to full blown adults. The experience was absolutely awful consistently. The only way to negate this slightly was to play in the morning (GMT) which was a slightly better experience but made finding games a slower experience.
While I'm certain that the experience can be similar on PC platforms, for the majority of the time this hasn't been the case for me consistently for decades. Being able to pick and choose servers and find favourites among them has also been a great way to find great communities. In fact thanks to this, there have been countless game types i have been lead to that simply wouldnt function on other platforms, personal favourite being "trouble in terrorist town". While I also hate "PC master race" stuff, the only place I hear it is hear on GAF or YouTube comments. 10/10 times its a console vs PC debate. Our experiences are complete polar opposites.
I'd hate to sit at a computer desk/chair and use a kb/m to game. I'd similarly hate to have to lug my PC to my TV to cast the image there.
I'm sure you have heard of the countless solutions to this so I won't bore you with a list debate. Personally steam in home streaming has been stunning on my medicore laptop to TV so I can only imagine most systems are far superior. The streaming can handle everything from any controller as in home streaming works it all out for you. You can even play civ with a gamepad as a mouse, which the game doesn't even support, and its actually pretty good if your in a casual mood. Point is for those inclined, this is easily solved with no hassle at all.
I used to play games on PC back in the Monkey Island days and again in the Half Life, Grim Fandango days but at this point there's no reason to. All those types of games will come to consoles, and I can still go buy Civ Alpha Centurai edition for my Mac when that comes out.
This seems a bit pointless as a debate. Console only games go to PC often and PC games often go to consoles too. This has been true and continues to increase as both are increasing in popularity. However the sheer number of games, particularly the older ones rarely make such moves whether due rights restrictions etc. In particular this holds true to many classic games without a massive push from multiple parties - see grim fandango.
Also again, playing alpha centauri on a Mac... I think that's PC gaming in my opinion, if you really want to catagorise everything