Data comes from outside your application code. Your algorithms operate on the data. A complaint like "There isn’t (yet?) a format for just any kind of data in .class files" is bizarre. Maybe my problem is with his hijacking of the terms 'data' and 'object' to mean specific types of data structures that he wants to discuss.
"There is no sensible way to represent tree-like data in that [RDBMS] environment" - there is endless literature covering storing data structures in relational schemas. The complaint seems to be to just be "it's complicated".
Calling a JSON payload "actual data" but a SOAP payload somehow not is odd. Again the complaint seems to be "SOAP is hard because schemas and ws-security".
Statements like "I don’t think we have any actually good programming languages" don't lend much credibility and are the sort of thing I last heard in first year programming labs.
I'm very much about "Smart data structures and dumb code works a lot better than the other way around" and I think the author is starting there too, but I guess he's just gone off in a different direction to me.
When I first encountered RESTful web services using JSON the ability to easily invoke them using curl was such a relief... (and yes, like lots of people, I went through a phase about being dogmatic about what REST actually is, HATEOAS and all the rest - but I've got over that years ago).
NB I also am puzzled as to the definition of "data" used in the article.