To paraphrase an analysis that I read awhile ago, Apple’s practices were found to be legal because Apple applied the rules unilaterally whereas Google would make backroom deals to alter the rules on an app-by-app basis.

Please take this with a grain of salt because 1) IANAL and 2) it is the middle of a workday break and I didn’t take the time to search for a source, just basing this off of memory.

If you want I can research this after work to provide sources and update my comment.