Right off, it's the Fourth of July. There's a holiday loaded with traditional activities in direct conflict with any major protests, so there's probably greater barriers to either getting the right to march/protest/whatever because of alternative events and a significant number of previous protesters are well, busy.

Also, public reaction outside of those who actually went to the tea parties was rather... negative mixed with a good helping of disinterest. That's certainly not helping bring the protesters out in droves.

It's poor timing and poor public relations biting them in the ***, more or less.