This is ridiculous. It is truly ridiculous. How can something that enables the user to efficiently control their AC cause "significant economic harm"???
I assume they have their own app and run ads/user analytics through it that make them money.
I have to wonder if you bought their products on the basis that they worked with HA, if you could have some sort of claim here.
But they want you to use their app.
And they've decided if you have a HA plugin, you won't.
So we do our research, and avoid scumbag companies when making purchasing decisions, or more likely, pick the lesser of a several evils.