Beyonce -- Slams Pregnancy Rumors ... But Doesn't Deny Them

Beyonce posted (and quickly deleted from Instagram) a harsh response to the rumors she's carrying baby #2 ... bashing the media as "low life people who have nothing better to do than talk about me."

It's an odd response to a pregnancy rumor -- it's not like reports are saying she's hooked on drugs or splitting from hubby Jay-Z. A simple "Yes it's true" or "No it isn't" would solve the problem ... but she opted for neither.

So we gotta ask ...