Staring at the Braille-like letters formed of gargantuan pixels on the screen with the finesse of sandbags being hurtled in place against the torrent of information pouring down his Ethernet connection, the notion of finely crafting the text of an email message with the pristine elegance of detail rendered to the precision of not just the vulgarity of a "dozen" but to the exactness of "12" typesetter's points escaped him like a pedigree-free canine chasing a slobber-laden ball.
I think it's a polite way of requesting that emails not use garish fonts and colors. Just imagine how many submissions he must get in illegible "handwriting" fonts.
Parent uses "Mutt", an email program using a UI so old it's probably endorsed by the Society For Creative Anachronism; the notion of "fonts" or "colors" in email, however garish, is incomprehensible to him. For that email client, content is ASCII text, nothing more.
I don't understand. Maybe because I've only used Mutt for 20 years. Is it a joke?