The letter itself is fine, but it's so vague that it can be interpreted in any number of different ways.
Can we stop pretending that Rowling is some kind of victim though? She's a billionaire who used her platform to spread awful views, and she rightly got slammed for it.
She's not a victim but her views aren't awful. Cis born women are going to have a different life experience than trans women, and at some points might be less privileged than trans women. That is not an awful view.
Trans people are literally like 0.2% of the population, and the left is collectively losing it over whether we should treat them as equals or as gods.