You're obviously trying to be thoughtful, and to a certain extent this is entirely subjective. If you, as any decent person would, think there are lines that you do not cross and that you treat service professionals with respect, then where is the line? You definitely don't throw shit on the floor intentionally, but you also don't offer to help cook, which you might at a family dinner. Every non-shitty person person will land somewhere in between, though hopefully a good ways away from throwing shit on the floor.
I think you're just running into a situation where your line is in a different place than other folks', to the point where you're a little out of step with the level of "help with the chores" that most people expect at a sit-down restaurant. If you continue to treat staff with respect, thank them for their help, and (if culturally appropriate/economically necessary) tip generously, then you don't have to feel bad. My wife waited tables and tended bar for many years, and it's not the specific tasks that are part of the job that ever made it feel degrading, it was people treating her shabbily and acting superior. No one expects you to clear the table when you're out; just don't act like you're too good to.