Predictably, you can find the actual DOJ letter to Montana quickly with Google, where you'll immediately discover that the letter is the result of a cooperative process following a rash of sexual assaults on campus, and was not in fact a new nationwide speech code for universities.

Thank you for telling me. I was wondering what those letters WSJ in domain name and those "Wall Street Journal" headers on the site mean... and now I know!

>>> and was not in fact a new nationwide speech code for universities.

The letter itself is not. However, it is intended to be used as a template policy for other places, and it significantly reduces the bar that needs to be cleared before speech can be punished - in part by removing any objective component - and introduces possibility of students being punished before the investigation is even completed. How speech codes could do anything about assault - which, by any sane definition, must involve physical action beyond speech - is completely incomprehensible. Even if change of the rules were necessary to prevent assault - which is doubtful as assault is already illegal so old rules should work just fine - speech limits have nothing to do with assault.