All true but the OP was asking why some US broadcasts look so bad and the reason is that bog standard NTSC is an inferior format compared to the stuff we are used to seeing in the UK (SD or HD).
Yes, but nobody uses "PAL" anymore, we're in the land of HD broadcasting where everything is 1080i. Well, aside from a few Freeview SD people living in the past.
PAL is higher resolution and has better colour reproduction compared to NTSC. It undeniably gives a better picture.
Now it's 1080i 50hz vs 1080i 60hz. The advantage of 50hz is it can show film without judder simply by speeding it up from 23.976fps to 25fps. Although, it is of course then sped up. Whereas at 60hz, pulldown has to take place and that introduces nasty judder. Hopefully one day they'll introduce proper 24hz for TV broadcasts too.