This new policy of 'if you don't like it, don't look' doesn't seem to be about making Mumsnet a safer place more welcoming and inclusive place, it seems to be more about 'look the other way if you are offended'.
One issue with this is that once threads get into active, people then post in the wrong place. Explicit threads won't stay on the Sex board, they will migrate onto chat and AIBU and anywhere that gets more views. We see this all the time with various topics.
Changing the policy so that you only need to have been a member for 7 days before posting on creates another issue of course. It is much much easier for sex trolls to join and start harassing people and messaging them off board. I guess that might help revenue if you are getting streams of re-registering sex trolls coming in.
MN used to take safeguarding seriously.
I also think this actually will exclude people from getting support. You now either have to choose to hide the board and therefore if you have a question or an issue about sex, you can't ask in the right place. Or you have to enable it and see every conversation.
Imagine if you are a Mum with young kids, sex has gone down the pan and you want some advice. You might not want your partner to see it. Your choice is: hide the topic and don't get that help you'd like. Or enable it and risk your kids or your partner seeing the threads on your screen.
This is a separate conversation to the very valuable safeguarding conversation about the sex chat threads.