It's true. I really only like New Mexico and Maryland's. Other than, of course, Texas' -- which is the most iconic and badass.
I didn't actually think any of this was funny -- I should add a "serious" tag. It's totally true that nearly every state flag should be tossed.
Most of them are bad flags, but not for the reasons listed. Here's a nice episode of the podcast 99% Invisible on this topic (and also a summarized article, if you don't want to listen). Essentially the principles of a good flag design are:
1. Keep it simple
2. Use meaningful symbolism
3. Use two to three basic colors
4. No lettering or seals of any kind.
5. Be distinctive