How do I always end up with purple? I pretty much wear blue, green, and black… no red

Yep. I wash a load of whites about twice a year when I have to make a special appearance in particularly white special clothes. Anything else goes in together.

It can change on a structural level through learning; why would learning beliefs be any different? (Over time through repetition, not a one-off thought causing permanent changes.)

https://www.verywellmind.com/what-is-brain-plasticity-2794886#toc-types-of-neuroplasticity

Why do you guys think I meant consciousness or the mind when I said brain?

Edit: actual question. What am I missing here, or was I just misunderstood due to something about the word choice?

I don’t totally get your analogy but I’m aware of the difference between mind and brain. I said the brain changes, not the mind. Beyond just the brain, yes, the rest of the nervous system changes too.

How is “brains are all capable of changing based on our experiences” different from “ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli”? (Other than the obvious fact that nervous system involves more than just the brain)

I would say your views ARE how you think and the product of how you think, and these are reflected in the brain. There is no prepackaged brain set for these or those beliefs; through neuroplasticity our brains are all capable of changing based on our experiences (including our mental experiences/how we process experiences in our brains.) Albeit, there could be genetic, chemical, etc factors which could predispose people to certain ways of processing info (eg. neurodivergencies) too.