And rationality is defined as the opposite of whatever is doing things "on vibes" is. You said it yourself, you are going with the vibes on your investment instead of reasoning and logic. And with so little information as there is about Anthropic's IPO reasoning and logic to invest are hard to come by.
Have you ever heard the story of Buridan's ass? A perfectly rational donkey placed precisely midway between two bales of hay; it has no logical reason to prefer one to the other, so instead of picking one, it starves to death. That donkey was irrational, not through lack of logic, but through having too much of it. The donkey who picks which bale of hay to eat first based on vibes is more rational than the donkey which completely rejects vibe-based decision making.
I bought US$350 of stock in some random Australian microcap because my dad worked there in the 1980s. Worst case scenario I lose US$350. And I get to have some fun conversations with my dad. What’s irrational about that?