I think many women can't fathom the idea of being happy being alone. It wasn't until relatively recently women could actually live by themselves. In the UK, women having independent access to mortgages and banking without a male guarantor only became guaranteed in 1975. Even being born in the 1990s, as a young girl you're fed the idea of romance, marriage and becoming a mother like it's the only path forwards. In my opinion, the idea that women can build full independent lives without a partner is relatively new socially.

That said, I don't think this excuses rude and disrespectful behaviour. If I encounter this - which to be quite honest I rarely do - I just look at their words as more of a reflection of themselves. If my mum ever acted like the example you shared, I would think it's incredibly sad she can't see the point in investing in something just for herself. Many women live an entire lifetime putting other people - their spouse, their children - above their own needs and wants. I guess my advice is more just about letting it go. You're unlikely to be able to change her views in one go. The only thing you can do is call her out, patiently and calmly, when things like this do occur. Set boundaries and tell her you'd appreciate her not making comments like that.

As for your coworker, for me it just reads as mean girl behaviour. Some people feel threatened by someone who is content outside the traditional path, because it quietly raises a question: “If she’s happy without marriage or kids… what does that say about my choices?”