[Controversial] What identities are identifying that way "sufficient" for?

[sissy-bloke.livejournal.com]

I would guess that lots of us would agree that someone is whatever gender they say they are, but what kinds of identities is that logic suitable for?

Someone claiming "I am a cat-lover" would probably be pretty uncontroversially accepted as a cat lover.

Whereas a lot of people would balk at agreeing that someone who says "I am a pineapple" is indeed a pineapple. (Obviously I'm using a silly example, somewhat less silly ones to follow.)

What is it that makes one identity true by virtue of claiming it and one unclaimable?

( What about the following examples? )

Edited to add "controversial" tag and to clarify that I am not trying to say that someone claiming any of the above examples cannot actually be what they claim - some of those claims may be perfectly valid and I'm trying to tease out what makes an axis of identification something that is based on what a person says and what doesn't.

Edited to change my original examples. I tried to use examples that would prompt discussion, but I realised belatedly and thanks to some commenters that they would probably prompt discussion about things that were unrelated to my original question and had the potential to cause shit-storms, for which I apologise. I hope the examples I've used now are less controversial, but please pick me up if I've mis-stepped.