Yes blacklisting should deny the friend request too, and there should be a rightclick option to deny a friend request as well as to report RMT. That said, there is still a solution to the specific problem people are reporting (not being able to easily blist someone who tries to friend you), and that solution was already posted in this thread. To say it again:

Add /flist deny <r> to the blacklist macro that you have already made because it's just a good idea and there's no reason not to have one. The macro should now look like:

/flist deny <r>
/blist add <r>

This refuses the friend request and blacklists the last person to send you a tell. No need to go through the friend list and manually decline the request. No need to then go look for the tell to blacklist the person. Just one button click. Done.

Assuming this works... Does the /flist deny have a confirmation box or something that makes this not work? I haven't tried it, because I have yet to be hit with this tactic on my server.