There was probably a grain of truth somewhere before everything became horribly confused. No, essentially, this is nonsense.
PDF files can have JavaScript embedded in them, if the creator puts it there. That's still true, it didn't go away. Nothing changed.
Perhaps some email systems block PDFs with JavaScript - though perhaps some email systems block PDFs entirely, it's equally possible.
You shouldn't be bulk emailing PDFs, it's a bad idea. Put them on a web site and email a link.