You're looking at corps the wrong way. I don't particularly care for working with formal groups in games either, but in hellMOO it basically just works out to a secondary chat channel full of people who (probably) don't want to kill you, who can help you do shit you need to do, but otherwise wouldn't be able to, who (potentially) could strike back at someone who's fucking with you, who will (sometimes) save your ass if you get into a bad situation, like being stranded on a ledge with no medical supplies and a broken arm (or you get cancer because an abom ran past you in the street and need a high-level crafter to make the cure), and being in a corp makes contracts available, which is almost always more lucrative than just doing your own thing, not least of which because they often pay you for doing what you would be doing anyways.
Actually, I suppose all that depends on the corp you join. Every one I've ever been in has been like that. To simplify the selection process: just join KREW. It's run by helpful veterans and its rules boil down to "help your corpmates and don't start shit with other corps".
Even if you're not in a corp you're still not
very likely to be randomly killed, unless you cross the wrong person, but it does increase the number of people who wouldn't be afraid of killing you for shiggles/stealing your stuff, since you have essentially no recourse against them if they do. Basically, it replaces hard coded safety with social mechanisms: sure, you
can pick up a gun and try to kill someone, but their friends can come and fuck you up for it. The most important thing is to not piss people off, and (in ascending order of importance) to endear yourself to them by being hilarious, good tempered, and not a moron.
If you look at the setting, shit that happens
is roleplaying: everyone is damned to a twisted form of immortality, stuck forever in a hellish post-post-apocalyptic wasteland, and they've all been stuck there for over a hundred years at this point (I think, I'm not sure when the Fall happened), leaving them all sociopaths. Essentially nothing they do can have a sweeping impact on the world as a whole, so they all just kill people/hideous mutants for cash, get drunk, and throw molotovs at each other. Would you do any different in their shoes?