That's because regular (non-HD) TVs use interlacing to create "better" pictures.
(Old skool Amiga users might remember "interlace" mode in DeluxePaint).
Shite for detailed graphics, or anything with a detailed user interface.
If you've got a TV-out on your computer, give it a go - it's staggeringly hard to read text on the Start Menu or whatever. Even with relatively large fonts.
I've got two of these badboys on my desk at the moment.
You pay a premium, but **** me they're beautiful.