Brown is a University, so that endowment funds research as well as tuition support.

And even beyond that, comments that bring up endowments usually come from a misunderstanding of what an endowment is. Its not like Brown has a bank account with $3B in it which they can access whenever and however they'd like. Endowments pay out a certain amount of money each year (I think its around 4% each year for most universities), and usually have strict stipulations on how its spent.