but against tethering your personhood to outside things

Yes, that's an excellent way to put it. I also think the the way we are schooled has much to do with it. At least in the US a school rarely teaches people how to learn things or how to examine a position critically. Most of the thirteen (now with pre-pre-school) sometimes 15 years of public schooling we receive is focused on memorizing a point of trivia then regurgitating it. Here's the important part: If you are right, you are rewarded. You are given a sticker, a homework pass, an ice cream, a special status. Most children spend their formative years being rewarded for being right and penalized for being wrong most of their day. Under such conditions how can one avoid having a significant part of one's self-worth entangled in the notion of being right?