Because the question is not “Which retail job can I get to help things going on, but doesn't actually increase my exposure possibility?”.

It seems to me the motivation is only getting the vaccine, OP doesn't mention the will/objective to help.

OP didn't say "I want to help retail, how do I do it without getting exposed ?” ?

His objective is to get bumped on the vaccine list by going retail with the least exposure. That's literally his statement.