I agree with the suggestion of asking about the blocking, if for no other reason than ascertaining it is supposed to be blocked. As already noted, sometimes firewalls come with a lot of somewhat generic site blocking and this might simply be caught up in one of those. Of course, it may turn out that it is intentionally being blocked for some reason, and you will likely have to accept it (assuming you want to stay on the job}. In any case, honest, polite inquiries into such areas should received answers in kind.
If it turns out to be related to the term "tobacco", I wonder if they would block both pro and con sites... including quitting tobacco support...there I go again, chasing that cat around the inside of the bag...