What? The IRS gave guidance for this in 2014! It's right there under item Q-6 in Notice 2014-21. https://www.irs.gov/pub/irs-drop/n-14-21.pdf
"Q-6: Does a taxpayer have gain or loss upon an exchange of virtual currency for other property?"
"A-6: Yes." (quote continues, but there you go).
I have no idea how folks came to the conclusion that 1031 swaps were ever acceptable, but it's always been clear that the IRS did not think they were.
TL;DR Don't get your tax advice from Reddit. (Or random commenters on hacker news, for that matter.)