It's an automatic feature that blocks profiles when the algorithm thinks the profile is a spammy profile. When you block words it scams the profile or something and blocks the profile.

It's not a good feature because it doesn't work correctly. I disabled mine. I will decide if a profile is spammy and not the algorithm.

So when you have your security filters on if more than 5 people of your followers blocked that account, it's gonna block it for you too also if the word bitcoin is in profile it might block it too