Question Tag problem!
Solution 1:
When speaking to Bob, Alice is not talking about him. She's talking about a man like Bob. A general man, who happens to be like Bob. So it's should he.
Bob, a man like you shouldn't do this, should he?
The general statement and its impersonal tag question is not a personal criticism; it's a hedged criticism, a criticism by analogy, a gentle prod in the right direction.
Using should you? as the tag question turns what should be a general statement, "A man like you shouldn't do this" into a specific statement which is directly aimed at Bob: "should you?" It becomes pointed, a personal criticism.