Unlike many of you, I don't work in an office in front of a computer all day. I bag groceries for minimum wage. So programming is just a hobby for me.
There are frequently days when I go many hours without access to my computer, so sometimes I must send emails from my phone. The reply you quote below, for example, was sent while sitting in the break room at work, with five more hours of work ahead of me and then other things needing done after that before I would have time to get on my computer. Yesterday, I sent an email (not to this list) at 10am that I would have preferred to send from my computer, but I had a very busy day away from the house, so I knew I wouldn't have computer access until after midnight that night. So I sent it from my phone instead.
The real issue here, IMO, is that people here are demanding plain text only in 2017. All good MUAs in 2017 can handle simple HTML gracefully. If one doesn't, then it's not a good MUA, precisely because it is 2017. If you require emails to be sent as plain text in order to be able to read them, you have a tooling problem that is your responsibility to fix. It is not reasonable to force other people on a mailing list to forgo their preferred, modern MUA just so you can continue to use a ridiculously outdated one. And yes, I consider any MUA in 2017 that cannot gracefully handle simple HTML "ridiculously outdated". Even a terminal-based MUA ought to be capable of parsing simple HTML these days and gracefully reducing it to plain text on your client's side.
Bottom line is that the plain text expectation on this list needs to die, and I'm done jumping through hoops to send as plain text on this list. If you can't read simple HTML in 2017, then you have a problem that is not my responsibility to fix.