That's a defeatist take that's been vastly debunked, someone linked the Matrix version and here is the XMPP one: https://gultsch.de/posts/objection/
In short, yes, building a standard takes some effort, but that serves your users and to future-proof your solution. Moxie's post boils down to "1- I know better than my users and I don't need input to protocol-design, 2- I'm not willing to put in the effort to standardize and document, 3- I reserve the right to change the deal for whatever reason if I ever feel the need" which is not a good look
In short, yes, building a standard takes some effort, but that serves your users and to future-proof your solution. Moxie's post boils down to "1- I know better than my users and I don't need input to protocol-design, 2- I'm not willing to put in the effort to standardize and document, 3- I reserve the right to change the deal for whatever reason if I ever feel the need" which is not a good look