I'm not really up on Hinduism, but one of the implications of "atman is brahman" would be that, reciprocally "brahman is atman".

Therefore, also it's not the case that "you can reincarnate into any of those life forms" but rather that all those lifeforms, including you, are incarnations of the same over soul.

So, you always already are both those forms and not, and have just forgotten it was so.

And, then, finally, when you do bad things to those other incarnations you are doing them to yourself: it's not that you have to reincarnate to have someone else do shitty things to you, but rather the case that karma is always already in balance.

Anyhow, just my shitty heterodox take based on a single poorly applied mathematical rule.

Be well, other self.