not every person in the FBI is a glowie out to kill you and your family

While I agree with the rest of your point about rushing to label these things, the actions these agencies get up to aren't really well kept secrets (and the secrets are probably even worse). Someone still willing to join despite knowing that taints themselves simply by that approval alone.

Especially as, given that reputation, you absolutely should treat every single one you see as someone who will do that because you are far more likely to be right than not.