> Also, he forgot that Elm (just like any other open source project) doesn't owe him anything. That's why many people take an issue with his tone.

We can't take issue with his tone by appropriating information about Elm's direction in an ex post facto manner. The guy - whatever guy - is a newcomer to Elm, picks it up, see an obvious deficiency, asks (quite politely, I might add) about a feature addition, gets a dismissive answer. That's the context. We can't apply Evan's* rationale behind the reply here, because the OP never had the chance to have it revealed to him to the extent of his interaction.

I'm surprised I have to point this stuff out. However understanding we may be, surely we can see why anybody is frustrated with being dismissed like this?

* Apologies, but I don't actually know Elm's author's last name.