Darth Bizarro said:

The prequels didn't ruin the original trilogy. If you don't like them, then don't watch them. It's as simple as that. Alien 3 doesn't ruin Aliens for me, because I don't watch it. I don't let the Jaws sequels ruin Jaws for me nor do I let the Matrix sequels ruin The Matrix.

While I agree with your arguments, don't forget that you can't watch the original trilogy in good quality without at least some bits of prequels inside (Hayden in EP6 for example). So I think I can understand someone saying that the prequels ruins the OT for him. It's not just the fact the prequels exist, it's the fact they are now mixed with the OT.