It’s about abusing the
power of a monopolistic position in the market. The power being abused is the
monopoly power.
If you don’t have a monopoly and do things your partners/competitors don’t like, they can’t complain that you are abusing a dominant market position to get away with it.
There’s nothing wrong with bundling. But when you have a monopoly on the market bundling suddenly is wrong and abusive even if it’s the right thing for your end users.
So we see time and again monopolies are knee-capped in the market and face these absurd fines, in the name of fairness and competition.
I have no doubt that some monopolies leverage their market dominance for some pretty atrocious dealings. I personally see nothing wrong with Google licensing the optional (but extremely popular) Google Play services such that it requires Google Search and Chrome along with it.
If they were unrelated then the experience of Google Play Services would be identical with or without the other pieces (Chrome and Search). I don’t use Android so I can’t say for sure, but I’m quite confident that the overall experience suffers without all three pieces together.