Obvious disability is a really good explanation, just as an aside. Telling someone who is genuinely ill that they aren't is damaging as telling someone they are the opposite sex when they are not.
I would suggest that having an Invisible disability is the polar opposite of Trans yet both suffer. Trans suffers from misplaced kindness that isn't deserved for what is rooted in a basically cruel, selfish, lying and narcissistic behaviour. The person with an invisible disability suffers the behaviour that a narcissistic person puts out into the world, cruelty, lied, no help or kindness. They each get the opposite of what they deserve given to them by others.
The gaslighting that happens to someone with an Invisible illness is really damaging to them.
To be then gaslighted by someone inventing something on top of being gaslighted that you aren't ill when you are, is infuriating to the Invisible disabled, who get the least sympathy going, not that they request it, it's just a tough life.
If someone is low energy from say Hashimotos, you can see that they are low energy, some may confused it with laziness, some with hasimotos may happen to be lazy. Someone else can't tell without blood tests and ability to read the blood tests.
This is why I think those with Invisible conditions fall for trans, as they wonder if there are some tests that haven't been invented yet to explain what's going on. I noted that they are abusing really vulnerable people and those are the groups they infiltrated first. They stole empathy that should have gone to sick people and stole empathy from sick people who have so few resources and I am sure not everyone claiming these illness in these 'communities' has them, which makes those with Invisible conditions look like charlatans and those who are sick not access the services and support they could because it's been colonised by fakes.