I do think how you define class is material to the discussion, it is your question, if you wish to challenge the respondent you should at least offer the benefit of your own personal insight.
It's called an exchange of views.
Supervisors are salaried, they're management, they wear different uniforms they have authority over others, some supervisors view themselves as no different to me or others, whereas other ones do and believe by virtue of their "success" we should be suitably deferential.
I respect individuals not positions, class is difficult to define along the lines of the trappings of wealth, Curtis Warren is a very very rich man, is he upper class?
I myself am a bus driver, the son of a bus driver who is the son of a docker and a hospital cleaner, I', the son of a care worker, who is the daughter of a scaffolder and a checkout girl, am I working class?
If, God forbid, I died tonight my estate would be worth in the region £210,000 to the benefactors.