i don't get paying rent to your parents

At dinner a few days ago, I mentioned how our local restaurant has jobs open. My mom assumed I was trying to job hunt (I wasn't) and brought up how if I got a job, I'd have to pay her rent. Logically I get why it makes some sense. But also I don't get it. I'm assuming it's a cultural thing which makes sense but like, if I haven't been paying rent before why now?

Kinda half a genuine question post and discussion over how it's stupid. I think I may also be opposed to it due to trauma. Even in a hypothetical situation, I really do not want to pay her rent (also because I don't know where the money is exactly going if that makes sense). The only exception to it I can see that I'm comfortable with it going to a co-pay thing which directly effects me if that makes sense.

Edit to add context: My mom is emotionally abusive and has provided a lack of support towards helping me + my sister in adulting. Whenever me/my sister bring it up, she'll tell us to "do it ourselves". I also don't have a ID or bank account (my sister does) due to my mom's neglect. I am able to get it myself but I feel extremely demotivated to b/c of my mom.