I disagree with the linked post, most people use 'REST' to refer to JSON-over-HTTP now.
You disagree with the guy who created the term REST?
Yep.
'Most people' can call it what they want, but in this context, they're not referring to a RESTful API. Search for 'REST JSON API' and you may discover 'most people' may be a subset of 'some people', and not a majority of people.