Whether or not it’s their job, one can still feel bad about doing it. When I worked retail, if we didn’t have something in stock (after looking), I’d apologize. Not because it’s my fault, but because I felt bad.
It’s the reason people don’t ask workers at retail stores for help; they (most of the time) don’t want to bother someone even though it’s their job.
I never invalidated someone's feelings. I merely stated that the logic they are using to validate their own feelings is flawed. It's very possible to change the frame of your mind through the language you use. If you remove the negative thoughts of "bothing" someone when they are merely trying to make ends meet, your feelings might change. In fact, by not bothering them, you may be giving their boss fuel for them to NOT have a job.
It’s the reason people don’t ask workers at retail stores for help; they (most of the time) don’t want to bother someone even though it’s their job.