FWIW, Stephen Miller, an immigration advisor, has, in the past suggested limiting issuing student visas to "hurt universities whose faculty and students had been critical of Trump" [0]. With this in mind, this motivation becomes more clear and this wouldn't be the first policy from this administration that does collateral damage to their base.
It's like the tax policy change a few years ago to reduce the mortgage interest deduction. This had a much bigger effect on expensive cities and suburbs which are more in Democratic-voting states (CA, NY, CT, NJ, MA, WA, MD, etc). The Republican party lost a few Representatives in those states but it was worth it to them to get the tax bill passed and stick it to the libs.
0 - https://thehill.com/homenews/administration/409436-trump-con...