Re: "E-Mail is a TEXT medium"
"I'm of the school that considers HTML email to be a security hazard".
Well, yes - because it is.
I've worked with a major email server software company for many years on data integration applications - and although that software does all sort of whizzy things, because that is what the market has demanded, corporately we only ever use Plain Text.
HTML emails are stripped back to Plain Text before receipt (by the client) and any that don't have a Plain Text counterpart are treated as toxic and are opened using rubber gloves and a pair of tongs.