Earlier quoted context omitted.
MicroG talks to Google servers and uses Google's infrastructure while breaking the terms of service (at least in case of FCM). Same goes with NewPipe - you're using YouTube without actually paying for bandwidth, storage costs or the video author. So you're not actually getting yourself rid of Google or tracking, you're just using their resources without paying the asking price. Use other alternatives instead.
Similar arguments have been employed against ad blocking. Users should be aware of the ramifications of their software decisions, but whether someone should download and use Google Play Services vs. MicroG, YouTube vs. NewPipe, etc. is the user's choice. From a privacy perspective, MicroG and NewPipe are much less intrusive than Google Play Service and YouTube, because the open source apps send less user data to Goog…
I'd feel similarly about having someone advertise a way to crack Slack enterprise features instead of using something like Matternmost.