It has been a bit less than a quarter-century since the publication of Murray’s The Bell Curve. Murray has spent that all of that time as a well-remunerated participant in the marketplace of ideas. He has never renounced his work, and he would surely reject the notion that it has been “demolished by scholars.” He is currently a fellow at a major conservative think tank, and, as we can see, he is still regularly invited to campuses to discuss his ideas and theories.
Liberals and scholars have politely explained why and how Murray is wrong for decades; he remains a prominent public intellectual because his ideas are useful to a white nationalist political movement underwritten by plutocrats. This movement currently holds power at nearly every level of American government, and Murray’s ideas are as influential now as they’ve ever been.
(also this is just a dumb concept).
Generally, the whole campus speakers/1st amendment discussion is silly. Yes it's a complicated by the existence of state universities, but like every single other working institution/community, campuses have a variety of issues to balance. Also like every single other working institution/community sometimes they will do it wrong. What exactly do you do when a sanctioned campus group invites someone to campus who promotes junk science asserting that a big part of your student population are members of a genetically inferior race? And if the line is not there, then where is it? There will always be lines and people just disagree about where they should be.
In my years of watching these types of controversies, my sense is that campus administrators tend to be much more likely to "dissuade" appearances of left-wing campus speakers, largely but not just because those speakers are more likely to have expressed views considered to be anti-Semitic due to their hostility to the actions of the state of Israel (whether or not the scheduled talk itself has anything to do with that). Even if we grant that the accusations of anti-Semitism are true (sometimes!), it is not clear why this is more disqualifying than having your life's work be propaganda about how black people are stupid.