Twitter Profile Editing Unavailable – How to Fix

I doubt you can do anything about most of these third party services, because they only create a profile out of what you have publicly provided on the internet in most cases. You can try complaining at these sites and request for a removal, but then that might open you up to more spam, perhaps? Revoking access would help only those legitimate app requests you have approved earlier.

It depends on more than just blocked status. If you had a public twitter account, for example, a blocked user could just log-out and view the public profile. A user can follow whomever they want if you don't have privacy settings set up to begin with.