One of these things is not like the other. Of that list only telemarketers harass you and don't take no for an answer. I try to be polite and decline whatever random thing they're offering but their scripts are designed to trap polite people, so eventually the frustration has to come out. e.g. upon declining to switch to TELUS, "what don't you like to save money?" I'd answer "no" simply because I knew their script didn't have a response for that.My first job was as a telemarketer.
Rinse repeat for fast food workers, line cooks, cab drivers, Home Depot greeters...
I know what you're saying about empathy for the worker, but there's a fine line here that doesn't exist with those other jobs you mention.
And I don't care how poor off the telemarketer is I absolutely cannot empathise with the ones who are perpetrating scams.