1.) The B117 variant has been in the US for weeks. We just hadn't been looking hard for it. So, changing travel restrictions from other countries with B117 isn't going to do too much for the overall spread of this variant in the US.
2.) There's more than just "statistical modeling data" to support that B117 is more infectious than other variants. Pretty well-done epidemiologic studies.
3.) The vast majority of reporters that cover healthcare items are woefully undereducated in basic science, basic statistics, basic terminologies. Sometimes, their reports are unintentionally sensationalized due to misunderstanding, sometimes, the sensationalization is intentional.
4.) The UM response could be argued either way as exceptionally cautious precautions, or a minimally-scientific PR-driven move.