Because it's not a $1.6 trillion dollar hobby or charity. They need to make money, full stop. This can't be emphasized enough.

As such, they view users more as a hybrid of volunteers and products. Then they monetize generally by selling the engaged users to advertisers. At this point I'm pretty sure they have financial models customized to individuals and they probably determined you're not worth providing service to unless you view more adverts... thus forcing you to engage more with the feed system.

They did what they had to do and you went ahead and accepted it; that's a good design. If you stop using them or switch to another service; then it would be a bad design.

What's the alternative? Put together some aesthetically beautiful design that lets users walk all over them while Meta foots the bill? That won't work because they'd go out of business. It's a matter of give and take.