Social status and respectability are not the same thing, a king may respect a servant because the servant is respectable and a beggar may hold a doctor in contempt because the doctor does not respect himself enough to treat others with civility. The social status of a doctor is always higher than that of a beggar of course, but that is inherited or part and parcel of his profession, his respectability is a part of himself and depends entirely upon his own behaviour.
But to put it all simply, a professional whose work requires education and money to enter is presumed to have had professional parents and has, therefore, a higher social status than one whose profession can be learnt as it is undertaken. A peon, on the other hand, is a Spanish or Mexican peasant and not of any profession as such, nor is a sweeper a profession, it is just a job. A salesman belongs to the merchant class, not the professional one and a hotel owner is in trade as is a factory owner or shop keeper. I do not know of any professional man who would invite a peon to a family dinner, let alone a wedding and I can not imagine where you have been meeting such a wide selection of people as this, the different incomes would usually keep them to different places of recreation if nothing else did.
On the other hand, if I met a peon at a party or elsewhere then I trust that I would have the good breeding to treat him with civility and respect unless he did or said something to forgo such treatment from anyone...snobbery is the armour of the socially insecure.