"I do find however there is a certain expectation that I have to attend the work Christmas social.
This is true, that's why I don't think such an intense focus on making everything "inclusive" is always helpful.
I agree with both of these - there are many reasons why people wouldn't want to attend and they should all be respected -- but that necessitates a sweeping cultural change in attitude, which probably won't happen because there's a lot of systemic ideology at play. For example neurodivergent people suffer a lot of subtle discrimination (eg being passed over for promotions from being seen as not a team player), mothers of young children and single parents suffer discrimination that has more to do with bias than actual work performance.
True inclusivity is about accepting that people are different and allowing them to be different and supporting their needs, not forcing them to conform.
And yes, stuff like participating or not participating in traditional cultural events are often (whether overtly or not) used as way to gauge if someone is "like us" and there's a known link there with systemic racism.
A lot of people have absolutely no idea of the amount of anger and hostility that comes out when you politely say "sorry I don't celebrate Christmas because I'm Jewish." Sure, some people are fine with it. But you'd be surprised how many people are very much not fine with it in a range of different ways, when it has nothing to do with them and doesn't affect them at all.
There's also the risk of being othered and I know MN tends to pooh pooh all this stuff, or act like it's all woke virtue signalling, but othering has genuine issues. I mean I'm British; I regard myself as 100% British. My maternal family have been in the UK for 130 years and my paternal family have been in the UK for centuries. I don't "choose to live here", I was born here to British parents. I'm just as British as anyone else. The fact I'm Jewish doesn't make me any less British. But it's obvious both from comments here and ones I've had in real life that some people don't regard British people to be properly British if they happen to also be Jewish, which is just racist. That kind of mentality needs to stop, and no amount of re-naming Christmas parties is going to help, it just makes things worse.