Why can't I play with my stepchild?

When my older kids were small, I played minecraft with them on a server. Now, with the nwe version of minecraft, I can see that I am no longer allowed to play with children under 18 or something like that ... to "protect" them... unless I set their age to over 18 on their microsoft account.

I'm sorry (Actually, I'm not) but this is literally the stupidest thing I have every encountered. The while plan with getting my stepson a computer and buying minecraft was so we could play together, and now we can't. I've googled it and done all kinds of stuff but... jesus, what the hell happened? Did you guys wake up one morning and decide to repeatedly hit yourself in the head with a hammer or something? I am both furious and extremely disappointed.