1. What does "liberalist" mean?
A liberalist is an advocate of liberalism, an individualist ideology borne out of the Enlightenment. It is a broad term that could describe a proponent of classical or social liberalism, depending on preference, but the term is a declaration of opposition to collectivist ideologies such as socialism, communism, feminism, Islamism and fascism.
2. "How can you have a collective of individualists?"
"Individualist" does not mean "individual". "Individualism" refers to the principle of the primacy of the individual in society, rather than the primacy of the group, according to standard English definitions of the word "individualist".
"a doctrine that the interests of the individual are or ought to be ethically paramount" - Merriam Webster
"the idea that freedom of thought and action for each person is the most important quality of a society, rather than shared effort and responsibility" - Cambridge