Flagging is just if you get downvoted enough, really. Posting spicy enough takes will generally get you flagged, but that's just how it goes sometimes.

FWIW I largely agree with you; a duopoly is only one more choice than a monopoly, and both Google and Apple have done a variety of things that annoy me. If I could pick a third option I would, but it's essentially impossible to enter the market at this point.