The cost of misgendering a cis person is that they feel weird.

Let's be clear that is an assumption. I understand that there is a shit ton of fake astroturfing going on, but not every single story of detransistioning is lies.

For a more personal experience point to this:

When I was a teen, transness wasn't really talked about, so a cis male being un-masculine "had to" mean they were gay.

Cards on the table, I'm bisexual. But only for a single digit number of men. I'm effectively cishet.

But with how many times I heard that I must be gay, from bullies, from well meaning folks, from strangers... it added significant additional turmoil to my toughest times as a teen. Suicidal ideation tough times.

And now, over a decade and a half later, I'm still not a particularly masculine man in a standard ass cishet marriage with a kid. And I'm happy and comfortable in my identity.

So I have a tough time hearing this repeated narrative of "there's no downsides!"