Edit: I agree with with tim's answer here: https://meta.stackexchange.com/a/11986 What are some justifications for not implementing it this way?
It doesn't really make much sense to me- I've lost 450 rep from bounties, so that means I've earned that much rep. Why must I lose the most basic privileges? Clearly I've demonstrated that I can follow the community guidelines to an acceptable level. Why not make it so that certain privileges are irreversible once you've earned them (unless a moderator manually bans you for something)?