There are perfectly amicable ways of monetizing open source. The most common example is selling a pro version with additional features that go beyond the basic

There are perfectly amicable ways of monetizing open source. The most common example is selling a pro version with additional features that go beyond the basic use case. That's a well-understood model and shifts the discussion. Trying to diminish the open offering by adding ads, even if removable, is perceived as taking away something