From looking at some of the statements from SNP MSPs including the Equality convenor, I think the issue is at least partly that they have decided that any women who have concerns or questions are 'anti trans', have labelled them 'bigots' and will not countenance listening to anything these women say. Not a word. Doesn't matter what anyone says, how politely or how reasoned, evidenced and referenced the argument.
This is backed up by my emails on the subject being responded to with either thinly veiled contempt or ignored altogether. (As a constituent, and of course I am always completely polite.)
This maybe worked while it was only a tiny proportion of the populace who were aware of the issues. But that proportion is growing, and it becomes quite difficult, at some point, to write off half the populace as 'fascists', or 'bigots', or 'uneducated'.