Email can have multiple parallel payloads in different formats (see MIME). It's part of the spec, not a hack.
The OP is suggesting that if LKML gets multiple payloads where it can understand one of them it just selects the one it can understand. This is what other text-only clients do.
They're not suggesting parsing html into text (tangentially, if they were, there are much better approaches than the one you linked. One of the most commonly used ones is originally by Aaron Schwartz https://github.com/aaronsw/html2text )
The OP is suggesting that if LKML gets multiple payloads where it can understand one of them it just selects the one it can understand. This is what other text-only clients do.
They're not suggesting parsing html into text (tangentially, if they were, there are much better approaches than the one you linked. One of the most commonly used ones is originally by Aaron Schwartz https://github.com/aaronsw/html2text )