Like Tesla, Palantir is an ideological investment for many, and likely why it's so over valued. Retail investors buy these stocks because they're buying into a world view. Tesla's is obvious (and it's not about green investments). Palantir's is a little less so, but they have built up an image that's right wing (but mostly not culture war), military-coded, and layered on American exceptionalism. They sell to the CIA, they sell to ICE, they help private healthcare companies milk their customers. This is all part of a world view that many people are in favour of, and Palantir represents it well. Andruil will likely do well for similar reasons once they go public.
This is not really to fault them. I see the company as far more mature than Tesla. They've cultivated a brand that works well for them. This is also not intended to be a criticism of Palantir investors, there are many reasons to invest, and even if you subscribe to the above that is of course your right! Many people invest for ideological reasons, myself included, and that's fine.