PC "Back story", why is that a thing?

[Mr.Moron]

We're specifically speaking of character background and choices that pertain to that.

No one said anything that can reasonably be taken to saying "no choice exists outside of backstory creation" -- that is a canard and strawman purely of your own creation.

Nothing I said can be constructed to be a Strawman. "Strawman" does not mean "somebody analyzed my statement in a way I dislike", or that "someone drew conclusions other than what I intended". A strawman is something specific. In order for something to be a Strawman I must:

A) Argue against a point that you didn't make.
B) Claim that my defeat of the argument means that your position is false.

https://en.wikipedia.org/wiki/Straw_man

The so-called typical "attacking a straw man" argument creates the illusion of having completely refuted or defeated an opponent's proposition by covertly replacing it with a different proposition (i.e. "stand up a straw man") and then to refute or defeat that false argument ("knock down a straw man") instead of the original proposition.[2][3]

In that post I pointed out what I believe to be a natural conclusion of the statement you made:

If the DM is just going to hand me a backstory, and say "here's who your character is, live with it", I might as well go play a CRPG instead, because even some CPRGs have more choice than the no-choice that DM is giving me.

I made no arguments against any point. I have not for example claimed that it is wrong to say that CRPGs are inferior to TTRPGs. I've made no claim on the issue of if "some choice" is superior to "no choice" or not. Simply pointing out an implication of a statement is not a Strawman. If you want to claim I missed context or lack reading comprehension such that the logical implications I draw are false is one thing. However, those things aren't a Strawmen.

Given the texture of this conversation I don't think it was unreasonable of me to read the statement broadly. The entire thrust has been about the merit and quality of a game being contingent on the degree to which player-written backstories are accepted & Incorporated.