I just downloaded it the other day. There were a couple of pages worth of 'free email offers' or whatever you call them that you could sign up for. I think I had to uncheck them all - saying I didn't want them. Maybe you didn't do that? I suppose that's what keeps Paltalk free.
I haven't gotten any junk mail from them, but do have quite a few pop-ups when I use it. At any rate, I'm glad I figured it out - have been enjoying what I've heard so far immensely.