Most of Unity's revenue does not come from licensing the engine. It comes from their "services" portfolio, which includes advertising and other tools for monetizing, including via IAPs (although they don't take a cut of IAPs, they offer tools to help implement them and improve monetization e.g. A/B testing). I agree it was a bizarre attack at his customer base, but it makes sense given Unity's merger with Ironsource (mobile game advertising giant).

The message seems to be clear: Unity is for people who want to make games that make money, not for indies who want to create for the love of craft.