You forgot about input lag, which occurs on most ish HDTVs. This type of lag is caused because TV wants to show screen at highest quality which takes some time do improve image. This type of lag makes playing dust UNPLAYABLE as you LITERALY can not aim because you don't know what the person will do. That valuable second or two of lag means life or death.

If you have ever seen me playing and I go negative, I'm using HDTV and I justvtry to run slave medic or links/hives

YES. When you move with right stick, there is like a half second delay for it to appear on screen and that makes it unplayable as you would have to predict what enemy will do to move before but you can't.