Never had any tearing on any of my 360 games,
You mean you have not noticed it, there is a difference.
its down to the quality of your TV/Monitor it seems.
No it's not, it's down to games being releasing without vertical sync enabled.
Either they are not putting the effort in to optimise a game, or the 360 is punching above it's weight and struggles to hold a consistent frame-rate, I'd guess it's the latter since only the 60fps games seem to be affected.