It's an interesting debate. I think that in both this trailer and the other clip that's done the rounds, Walsh comes across as thoughtful and articulate, and it's quite a shock to discover he has such reactionary views on other topics.
It's an illustration of the weirdness of this particular debate, and it's proving confusing for a lot of us. Traditionally, there are a set of subjects where the stand you take marks you out as progressive or reactionary: abortion, gay marriage, taxation, capital punishment, minimum wage, maternity leave and so on. Most of the time if you know a person's view on one of those issues you can pretty accurately guess their views on the others.
The trans issue is different. Why? It's because the so-called progressive left have collectively adopted a position that is literally insane. That's all you can say about it. The idea that humans can change sex, or that there are more than two sexes, or that sex is a spectrum, or that a violent male criminal who puts on a dress and calls himself Stephanie should serve his sentence in a women's prison is insane. Unlike topics such as abortion or gay marriage, there is absolutely no possibility of having a reasonable debate about it because the people who believe in this stuff are far outside the outer borders of rationality.
So there are really two groups of people opposing gender ideology. One is people on the right who aren't experiencing any peer group pressure to believe in this, because it's not part of the package of things right-wingers believe in. The other is people on the left who are still capable of independent thought - and have the courage to say so. It's much harder if you're on the left to speak out about this stuff, which is why much of the opposition, particularly in the US, is being led by the right. It's an easy win for them. All they have to do is not be insane.
And that's what makes it really important that those of us who do have progressive views continue to speak out about this issue, because we don't want this to become a right-left issue. Because a lot of ordinary people who are not invested in this debate are simply going to vote for the guys who aren't insane.