Here's what I tell people when I mention Erlang and then OTP: "OTP stands for 'Open Telecom Platform', but it's just badly named due to old corporate history at Ericsson. It's more of a general development framework that includes generic versions of design patterns to build pretty much any Erlang application."
I have never received questions after that about the name -- people get more interested by what it contains than what the initials stand for.
For the argument about 'core Erlang devs', the post you mention is:
1. not from a core Erlang dev
2. actually from the main Erlang developer of Cowboy, one of Erlang's most used web server/framework
3. Right that JSON is a pretty inefficient serialization format, full of ambiguities and with many undesirable limitations.
4. It's also right that JSON contains nothing regarding hypertext within its data type (ignoring JSON-schema) and is therefore a weird choice for the web and REST, where hypertext is fundamental.