I went to find what was actually said, and this traces back to a Daily Mail interview, that says the following:
Another thing he stood up for was transgender rights, making a statement in support following comments by J.K. Rowling, whom he knows through playing Newt Scamander in her Fantastic Beasts films. (He's back on set at the moment, shooting a third movie.)
He said he has many 'trans friends and colleagues' who are 'having their human rights challenged around the world and facing discrimination on a daily basis'.
Though he disagreed with Rowling's comments on the issue, he was alarmed by the 'vitriol' hurled at her on social media, which he termed 'absolutely disgusting', and which prompted him to write her a private note.
However, Redmayne felt that the insults to trans people on social media is 'equally disgusting'.
He said: 'Similarly, there continues to be a hideous torrent of abuse towards trans people online and out in the world that is devastating.'
I don't disagree with him on that. I just think it's a shame nobody's noticed that it isn't gender critical women abusing trans people. It's aggressive and abusive men. And they're abusing women just as much, and killing them exponentially more - but nobody seems to care very much, do they? Funny, that.
At all events, it's not a reverse ferret. He's just agreed that the level of pile-on she had wasn't okay, despite being part of it, now the tide is turning somewhat - in the UK, at least.