Urban dictionary sums it up really well IMO.
A word used when you agree with something; or when you want to recognize someone for being themselves, i.e. courageous and unique or not caring what others think. Especially common in online political slang.
For example:
META is based for open sourcing their LLM weights.
HUH? Why would I want them to let me into their club and what does it even mean for someone to “get into their club”?