I am both a PC gamer and console gamer. I have played FPS on PC, and of course, it is much easier to aim with a mouse than it is with a console controller. Having said that, I still much prefer free aim in GTA V on the PS3 and I don't have an issue with gamers that prefer auto aim/aim assist, to each their own. For me personally, it is just more fun knowing that I am getting my kills with no assistance from the game. I'm also the type of person that prefers setting game difficulties higher, and I feel like choosing free aim is GTA's version of setting the difficulty to hard. Everyone else in the free aim lobbies has the same challenges as I do, so even though I'm not as good at aiming at people as I would be with a PC mouse, it doesn't matter because everyone else has the same challenges and so we're in the same boat.
Bottom line, coming from someone who is a PC gamer and console gamer, I find free aim more fun to me personally BECAUSE OF THE CHALLENGE with respect to aiming, not despite the challenge. It makes me FEEL like I'm earning my kills and that there is an infinite amount of room to improve and develop skill so I never get bored trying to refine my aiming skills. Even though it is way harder than it would be on PC to aim, I still like it more than auto aim or aim assist. I don't seem to have an issue finding free aim worlds with gamers either, some rooms are full.
I also don't have an issue with people that prefer playing with auto aim or aim assist since GTA is set up so we never play with each other unless I change from free aim. That way it stays fair. Also, since GTA is set up so auto aim is an option, it allows people to enjoy the game the way they like to play on a fair level with other players. Rockstar is just trying to please a diverse group of gamers since GTA is basically a million games in one video game (racing, piloting, tennis, golf, etc). That way people can enjoy it the way they want to. Video games are supposed to be fun, so I don't mind if people want to play it a certain way that improves their experience. The only downside would be that free aim rooms will have less players, but honestly, I haven't had an issue finding free aim worlds that have lots of players in it, so it doesn't bother me. I have trouble finding races/deathmatches with people but I think that is due to how the matchmaking is set up by Rockstar, and thus, auto aim gamers may have the same issues.
And with people talking about skills, etc that each aim type presents, I would just like to say that in auto aim lobbies the fact that it is auto aim changes the game completely and thus new skills need to be utilized. Like the cover system becomes more important, constantly being aware and pressing the auto-lock trigger to find targets, using the controller's analog stick to bump up for headshots, etc. It just becomes a different game and new skills need to be developed in order to improve one's ability to survive/kill others. The best auto aim gamer will most probably beat the best free aim gamer if they both set their settings to auto aim, and the best free aim player will most probably beat the best auto aim gamer if they both set their settings to free aim. Obviously, auto aim reduces the need to refine one's ability to target an opponent and remain targeted, but everyone else in that room has the same advantage, and thus it becomes a different game and other skills must be refined. I personally don't like that kind of game, but that's okay, since I have the option to play in free aim exclusively.
Video games are supposed to be fun. I don't mind if Rockstar has it set up so more people can enjoy the game the way they want to play it (with the different aim modes). I don't have an issue finding players in my free aim worlds so it doesn't bother me if a ton of other people I could be playing with are in auto aim worlds.
Now the matchmaking system, where it's hard to find deathmatches and races with people (especially early morning or late night for some reason for me)... I want that fixed. But I think that is an issue all aim lobbies are having.