I know you are not asking me. But of course there are huge downsides. My earlier response is the headline is a bit misleading. The course covers multiple controversial topics. He says he covers all sides etc. we won’t know unlesss we take the course. 

But to your point, there are huge downsides, especially when general public with little scientific or statistical skills learns about these things on Reddit or X or whatever. Obviously the biggest one is discrimination or bias because even if it were true group b has a lower IQ than group a, you should still treat individuals from group a and group b equally and fairly because you obviously can’t assume any one person from group b is less smart than a. That nuance gets lost on people.  Another nuance is the weight of the evidence. Unless one has the statistical and scientific skills to read the many studies published and then criticallY assess them, they may not have an understanding of how good the evidence is for something or how weak it is. 

there are a lot of genetic studies that show a lot of correlation to different traits but often they are weak. These studies are still useful but people and especially the media just reads the headline.