Yes it might be a hint that you don't believe what you say, but that shouldn't detract from you saying being potentially correct. After all the truth value isn'

Yes it might be a hint that you don't believe what you say, but that shouldn't detract from you saying being potentially correct. After all the truth value isn't affected by who says something. I bet there were smokers who were part of discovering that smoking is unhealthy. The thing about pointing out hypocrisy is that you're actually lending authority to the person you criticize, you're saying that you believe in the side he's revealed to actually support.