What every person can do right now to combat this legally:

1. Perform a forensic review of the posting account. Most of them leave telltales that will lead you to their identity or group identity.
2. Perform a forensic review of the linked website, looking for the same information.
3. Repeat 1 and 2 for each relevant social media artifact, cataloging as you go.
4. Leverage the crowd. Summarize the (public) information you've found and publish it to all major platforms and social networks.
5. Begin reporting the offender. To the university, to the campus police, city police, state police, FBI, Twitter, and to whatever other platforms their content appears on.

My guess is the person behind this account is either a student or a UT professor or staffer. Regardless, threatening dox & harass at incoming students for political views is the dictionary definition of terrorism, so I don't think it's necessary to let this stuff go, turn the other cheek, etc. You need to become way more aggressive, not less. Just keep it legal and sane.