It boils down to the definition of class, and there is many.
The burgeois revolution in 1700
s and 1800s abolished the feudal classsystem wich where constituted by law. In the new republican paradigm everyone where equal before the law.
In our day we still have classes, but we dont have titles and property lended to us by the state, so its not so easy to spot it. In short: The upperclass is the people who owns the means of production. Throug this possesion they have more than average control over society and they are more than average wealthy ( capitalist/burgeois ). The lower classes are the people who dont own any means of production and therefor must sell theire labor to make ends meet ( proletariat ). As a individual a proletarian have little influence over society and is powerless against his counterpart the capitalist in any hypotetical conflict. The only way he can gain influence is by joining togheter with other proletarians. In the workplace they often form unions to counterbalance the power of the capitalist. In the political sphere they often form partys to pursue theire interrests. If they did not do this we would not have all the rights we posses today, and most people would have a worse life and the class difference would have been bigger. My point is that a politician who serves the interrests of the workers doesnt not belong to the upperclass, and to think he does is to follow a definition of class that only make sence in a feudal society. I have said this before, but I say it again: If I where to go back in time, let say america 1790. I would probably be a jeffersonian republican, because in that context it makes sence to be in line with jefferson. Today in our industrial society with supercapitalists who control large portions of our society, free-market-libertarianism does not make sence as a ideology of liberty and egalitarianism. The reason for this is because it does serve as a defence of the freedoms of the rich and powerfull, not the yeoman-farmer, the artisan and other small burgeois occupations in the early era of the american republic. This is probably why it also have lost it popularity over the years, because it doesnt serve the peoples interrests only the rich.
to get back on track, I would say that no working for another human being does not set the proletariat free. Since you guys know have important property is, you can say that the proletariat are free when they owns the fruits of theire labor and by that are no longer the proletariat. proletar= without property.