They want to hire Pedos so they do the bad stuff and can keep their mouth shut.

Fact free article.

But interestingly enough, for anybody who’s curious, the security clearance process doesn’t seem to actually include an in-depth review of social media or internet activity. So if somebody’s into kiddy porn and they keep it quiet in meatspace and don’t leave a suspicious money trail via bank records, the OPM might not catch it.

"The FBI is responsible for vetting government contractors, by looking into applicants’ criminal history, financial records and foreign contacts."

Untrue. FBI conducts its own background checks for FBI issued clearances. The bulk of clearances are processed by Office of Personnel Management (OPM) with about 80% contractors doing the work of background investigator (other 20% are OPM GS employees)

Hard to get past a second para when it's wrong. And yes, I've seen all sorts of weirdos get clearances or get clearances reinstated after - serving time for manslaughter, habitually jerking off in public, and screwing one's teenage stepchild.

Yes, it does happen.