Free assembly is one expression of democracy (though I am against democracy, don't get me wrong, I am against mobocracy), however you are correct.
Another expression of democracy is free association. It absolutely 100% does not matter who is deciding not to associate with you, be it a girl next door, a club of interests or an employer for whatever reasons, that's completely irrelevant. I want people to be free to discriminate or not based on their own ideas and believes, and you are telling me that you can't handle that freedom, freedom of association.
Freedom of assembly is absolutely not impeded in any way by any private party, be it an employer or anybody else. Freedom of assembly can only be impeded by government. The entire concept of rights is completely misunderstood by vast majority of people that have gone through the public brain washing system, so called schools, that teach you nothing.
Rights are protection against government abuse, nothing else, everything else is either an entitlement (that nobody should have) or an obligation (that nobody should be imposed upon by any government).
Corporations are a front, a fiction, they are a fiction and behind every corporation there is a person or a group of people. AFAIC corporations shouldn't even be established by government laws, government has nothing to do with business, a corporation in fact is a self governing body, nothing else. You may want to figure out where the word comes from in the first place, the only purpose of government involvement in corporation is registration. Registration of corporation is what 'citizens devised' (and it wasn't citizens actually that devised it, you are wrong on that too).
However I am not arguing pro or against corporate charter here, I am talking about the reasons that people start their own businesses, corporations or anything else. A BUSINESS, a business for the purpose of generating profits, not a 'corporation' for the purpose of incorporating a legal entity. Government shouldn't have anything to do with people running businesses, that is my point. Whether corporations should be legal entities that are given any special treatment? NO! Owners of joint stock companies that eventually became corporations for the sake of simplicity of regulations shouldn't be hidden behind corporate facade from litigation.
I disagree as a general principle with the entire idea that there should be ANY form of protection of private individuals behind corporate facade in case the individuals (or the company) are sued or become liable in any way.
Yes, I am against special privileges that government provides to anybody, anybody at all, including all people, all living or dead creatures, all legal or illegal entities. Of-course I am completely against the very concept of having any federal power over people in the first place and hopefully over time, given the facts of life, such as freedom of movement of information (the Internet), freedom of movement at all (transportation, immigration, emigration) eventually people do away with federations, with dictatorial entities that are trying to steal their property and lives from them.
Governments' "Limited Liability" garbage is what created possibility to create gigantic faceless entities, known as modern 'corporations' that removed private liability from the company owners. This is a moral hazard that government created and this moral hazard is what makes it possible for the modern stock market to exist not by virtue of the real business value, real earnings, long term goals, but by virtue of government created guarantee and protection that destroys the principle of running a private business that incontrovertibly adds value by its activity in a normal free market rather than extracting capital from unsophisticated 'investors', who are really unaware of what is going on around them. This is a moral hazard and it was created by governments.
Apple and Google or anybody else must be within their absolute rights (and I am an atheist, otherwise I would have added 'god given' there, as is I would say 'nature given') to come to any agreement among themselves to not hire you or anybody based on whatever criteria that suits them and you shouldn't be compelled under any circumstances to take any position within those companies.