If I was to guess I’d say it’s the only way they can do anything meaningful. If the goal is to curb google’s monopoly on the internet it would be neat to break it down and apparently search was a case that can be credibly pursued on antitrust grounds. Web integroty hasn’t yet reached its intended scope, even if everyone with minimal knowledge know where it’s going, “everyone sees the writing on the wall” is not a valid ground for legal persecution.