> Why care what the UK has to say about US matters?

Because US regulators are too lazy/corrupt/starved to do the job they exist to do. Someone has to reign in oligopolies amassing even more power and dominance, and it obviously isn't going to be the US, so whoever wants to step in, be our collective guest. This time it was the UK, next up is the EU Digital Markets and Digital Services Acts.

And yes, there are much more pressing matters, which others are dealing with. A competition comission doesn't have other duties than to block such obvious abuses.