AITA for only allowing a pet kitten in the sharehouse if the owner takes full responsibility?

We live in a sharehouse of 4 ppl. We are friendly - but not a particularly close-knit house: we don't eat together or hang out much, other than brief/polite convos in the kitchen or living room. I can go days without seeing some flatmates.

The point is - there's no drama - but we are in no way a family.

One of our flatmates wanted to adopt a kitten. I told them I'm fine with it, as long as they took complete responsibility for it, including any and all costs associated with it, cleaning up after it and generally just looking after it.

Now - I would LOVE to have a kitten. And I would definitely spend time with it, and more than likely help pay for treats etc. if allowed.

But since we aren't close, I don't feel comfortable them getting it unless they agreed up front to those boundaries.

The flatmate has now decided not to go ahead with the kitten and has called us ashholes who are selfish for wanting to get the good parts of having a kitten, but not willing to share the costs or responsibility.

I just don't see how it's feasible for us to share the responsibility of a cat given our relationships. Also, what about when one of us moves out?!