You keep saying "entitled to someone's attention" but talking to someone doesn't require any special entitlement or even attention. They can ignore you.

This is the first you've said about reading the room, too, so it sounds like you don't actually have an objection to deploying an "opener" - you're just assuming it's being done without exchanging a smile or something first.

And don't get pissy because you pushed back against someone pushing back against something, didn't actually agree with the something, didn't make that clear, and then were assumed to agree with it. If you leap to someone's defence but don't agree with half their comment you can just say that and it helps everyone.

I don't think there's anything else to gain in this conversation.