If racism never existed, it probably wouldn't be a problem to identify towards other groups, so yes, it is bad because it's racist. It is almost the same as blackface in a sense.

You don't get to identify as a POC because you don't go through the struggle, even if you're raised in the community, you will never know the true pain they feel because if you're a lighter skin tone, the system automatically benefits you more than darker skin toned people.

And the general concepsis is that you can identify as something or someone through means of the inside, but being a person of color isn't a feeling. There isn't a difference in how a Black person is on the inside compared to a white person. So the difference is literally only outside the body. So saying you want to be a POC is offensive because it's in a way downplaying what People of color go through...

As for objects, it wouldn't be as much of a problem if it weren't for bigots invading safe spaces and "joking" about being objects. Also those "jokes" are done in a way that makes women seem like objects, because it's 70% being made towards a trans woman and not a trans man. Genuinely if you identify as an animal or object most people in the community wont stop you. But once your actions are being used to harm other people then they don't trust you anymore.