I'm a pleb dear, just a pleb 
Having taken another look, it is clear that it is a thread about cakes. It is amusing. I think people have got all fired up and then when they realised it was a joke thread, they got angry at having wasted their time and energy on a joke thread.
Fair enough.
However parenting is a serious business and we all need to have a laugh now and then. Back in the dim early days of Mumsnet these joke threads were well received and provided much mirth and even a sense of community, a sense of a joke shared and even those taken in would be laughing.
Now it seems that Mumsnet is full of angry people who want to find offense in everything and everyone. Everyone seems so tense and angry and quick to blame. I wonder if it's to do with the mounting pressure on everyone these days?
I can see why some threads might be offensive, when sometimes a joke falls flat, but the cake thread was simply meant to lighten the atmosphere and to that end it was done with the best of intentions - to give everyone a laugh and to share a joke. It's a shame that it hasn't ended that way and has merely served to drive Mumsnet apart. So now it appears that the angry people want to accuse everyone else of being in a clique, being Mumsnet Royalty etc which is a pretty ancient insult. Whilst the rest are merely baffled at what the big deal is.
I am baffled.
I remember a great joke thread about someone whose dh wanted her to dress up as a cow during sex. The main joke was what all the other posters came out with. The comments are what makes those threads so funny. Perhaps if that thread was posted now, people would be angry because there really might be posters who dress up as cows and it's unfeminist and it could be alluding to domestic violence. It would fall flat now.
What has changed?