This makes it abundantly clear that violent, disruptive, pro-Palestinian protests on college campuses are dangerous and anti-American. Khamenei is desperate to spread his influence in the West and likely sees these protests as an opportunity to turn these radical liberal protestors into another Iranian proxy group. This should be seen as a wake-up call, not a compliment.
The questionable moral standing of the source doesn't make Khamenei's claims any less truthful. Israel is arguably carrying out a genocide in Gaza, and the US and other Western countries have been complicit in the brutal murders of tens of thousands of civilians. The focus should be on the horrible results of US policies and the suffering of Palestinians rather than this letter.