"And transphobic responses like this are left to stand like they're absolutely reasonable and not a form of hate speech, but those of us that call out transphobic posts and comments have ours deleted."
'This is why I left Mumsnet originally, its clear transphobic bias coupled with its majority boomer transphobic community."
'Such a nasty, spiteful place.'
'Still, I find it hilarious watching you all perform exactly like I expect you to.
Hence why I'm still here, for the entertainment'
If you have your own personal definition of transphobia that doesn't match that of the general public understanding, then by all means, you will personally find posts stating scientific fact and not complying with your philosophical belief 'transphobic'.
Mumsnet doesn't have to support your personal definition any more than the general public does. Therefore, if they don't feel that it is transphobic, they will not delete posts.
If you use language that falls outside the Mumsnet talk guidelines while making your accusations, then yes, you will have your post deleted.