...Becasue Google is the problem.
Specifically because Google is the actual problem! Isn't that abundantly clear?
Mind you, I use F-Droid and of course Aurora Store if I ever need anything from the Google Spy-Store which, fortunately, is hardly ever. Essentially, if you spend a little time looking around you can get just about everything you'll ever need without ever going near the Spy-Store.
P.S.: After you root your your phone, if you're smart you'll get rid of all the Google crap, especially Google Play Services and Google Play Store before you put your machine online for the first time. Given the smallest of chances, this pernicious software does everything it can to steal your personal info. It's so effective that it puts many viruses to shame.