Libertarians have zero problems with people cooperating and working together, because many worthwhile things are impossible to achieve by a single person. The free market is a real good example of that. Their only problem is when people are COERCED into working for a collective. Government is the only institution that can use violence or the threat of it to get people to do stuff together, and of course they have hundreds of thousands of armed agents in this country at every level of government to facilitate that. Corporations and non-profits can't MAKE people do stuff, they can only try to persuade them to act in the desired fashion voluntarily. Libertarians feel that people should be persuaded to behave in the desired fashion without the fear of being imprisoned or shot. People should be allowed to pusue their unique self interests, and yes we all do that, with as much freedom as possible, and that would include associating or not with others as they wish, or working and contributing as they wish. If you want people to cooperate in an organized fashion, all you have to do is to offer them something they want in exchange for their efforts. If organizations are no longer doing that, they should fail.