What an awesome question.
It's akin to the Alcoholic saying 'respect my position and who I am(and/or what titles I have), not what I'm doing'.
To answer your question, No, I can't respect an unrepentant alcoholic.
I can feel lots of things about them, depending on how distant I am from that person, but to respect anyone who chooses drugs over their spouses, children, family members, friends, job, God: no.
As for those who are battling addiction(making the decision to stop and doing something about it, getting help), different story.
From everything I've ever read/heard, recovery for the addict is a fight for life, for a lifetime.
How can anyone not respect someone who is willing to go through that?