Are these people entitled to the rights you're talking about? They're people, so I think you must say that they are.
OTOH, to all intents and purposes these people are behaving like a corporation. How can it be that corporations are denied those rights, but groups of people that behave exactly like corporations -- that are corporations, in all but name -- are entitled to them?
A collection of individuals operating in principle like they’re an LLC, but not contained within an LLC, don’t get the protections that an LLC get. They get individual personal unlimited liability.
For the same reasons that me operating as an individual gets taxed as an individual, but me operating through a LLC wrapper gets taxed as an LLC.
We’ve made up these arbitrary rules whereby LLCs (sometimes) get a different set of rules to real people.
Nevertheless I don't see liability or tax differences as fundamental: I think that, even if there was no legal concept of a corporation being a (kind of) person with special protections, functionally similar structures could and would arise. We already have liability-waiving EULAs everywhere for software, which 99% of people accept without a second thought; perhaps this concept would be much more widespread.
I also think that most people who complain about "corporations" don't carefully distinguish them from other ways of clumping people together for business reasons, like partnerships or trusts -- I think the resentment is mainly around the size and wealth of these clumps. And I think that the differentially wealth-generating tendency of all these people-clumping arrangements comes primarily from the efficiencies (and additional possibilities) afforded by letting the people in them specialise their work, rather than from liability and tax differences.
But admittedly that's my own speculation.