In one hand, the user should have ownership of their computer, and what happens in it. The user should not be prevented from testing and modifying whatever occurs in their memory, in the same way, I can load Adblock, or Reddit Enhancement Suit, to make my experience on a website better.
On the other hand, online gaming has become a sport. Having cheaters in-game is almost like bicycle racers using enchantment drugs for a competition. I would hate to lose a bicycle race for having another athlete using illegal unhealthy drugs, as I would have to lose an online game for other players paying hundreds of dollars for a significant unfair advantage.
For me, there should be a new kind of law that would cover gaming cheating behavior under unfair gameplay. Users are detracting from the experience from the other players, who are playing the game on an even playing ground.
I find GTV 5's strategy particular interesting, that instead of banning cheaters in online servers from playing, they just moved players to a "cheaters pool," in which cheaters can play with other cheaters. It still allows everyone to play the game, but now they are put up against other players who also have an unfair advantage, and have to compete for a better strategy.