PC gamers are never happy, unlike their consoles counterparts they seem more willing to put down at every turn. If the game is great and it has no DRM, they bitch about hardware requirements and why it doesn't run on their 8 year old geforce 4. If the developer actually tries to protect it's intellectual property (you would too if your money was on the line), people bitch about how their rights as a consumer are being violated and how the game should be pirated. If the game doesn't measure up, people still encourage piracy (kind of wonder why people would still want to pirate the game even if it's bad, I guess a lot of people are just dickheads who are proud of the sole fact that they steal from developers.)
Seeing the patten here? In this day and age, the anonymity of the internet has lead to an "I don't give a shit about developers, they just owe me games" mindset. Piracy is exactly what DRM is addressing.. People buying one copy and foregoing payment by distributing installing on many machines. As someone else mentioned, DRM is way less invasive than most copy protection schemes and doesn't require a client to be running all the time.. Funny thing is that steam requires internet all the time, yet people are opposed to copyprotection/DRM on the grounds that it OCCASIONALLY requires internet.