Well, as it happens, the only example personally known to me at present of someone who contemplated getting a job and changed their mind because of the impact on benefits

Unless you regularly interact with the type of people who live in underclass ghettos, or the class of people sometimes called "white trash", it's not surprising that you personally haven't met people like this.

(Famous examples: "Abstinence-only" sex ed in schools doesn't stop kids having sex, but it does make them more likely to get pregnant when they do. Restricting the availability of contraception increases the incidence of abortion and single-parent families, both of which the opponents of contraception usually say they're more strongly opposed to.)

Setting aside the validity of these examples, I note that none of them are actually examples of incentives.

Let's continue that discussion when you're prepared to engage seriously with what I'm saying.

I am engaging seriously. I merely applied your epistemology to a slightly different domain and suddenly it becomes clear how silly it is.

OK. So if a trans person's brain structure, personality, behaviours, etc., were found to be nearer typical-female than typical-male, would you then consider them something other than deluded/hallucinating/bullshitting? What sort of differences in brain structure would be most relevant? (Brain structure is kinda hard to explore, beyond the very coarsest features; what if we couldn't tell about brain structure but their personality and behaviours were "more female than male"?)

Frankly, I have a hard time believing that something would mess up the development of precisely the sexual characteristics expressed in the brain.