I have to disagree there—this is a complicated domain and I'm afraid it would be quite difficult to get right. For example, I'm sure there are quite a few legit companies posting more than 3 times a year. Excluding them wouldn't be a good strategy; they might well be some of the best places to get hired.

You're certainly correct that there are bad actors, on both sides of the hiring transaction—that is, there are fake jobs and also fake job applicants. Unfortunately it is a hard problem to solve, and we have no particular expertise in it.