I don't understand why people are surprised. There are loads of education topics that are off limits. You can't get a VISA if you are studying certain hot topics, particularly those that can be weaponized.

Are people really arguing for Bashar al Assad's right to study molecular biology?

Why would you educate the engineers of an enemy state on how to build smart weapons? Even if a 20 year old left leaning engineer doesn't want to hurt anybody now, who knows where a lucrative career path will direct them in 10 years time.