Let's leave politics out of the discussion because both sides of the aisle can easily defend their positions on this.
Colleges are closing up shop to reduce their **liability** (just like the sports organizations) and spread out the population across a larger area in case hospitalization is needed. Colleges really don't want to be dealing with 20% of students in a dorm with fevers that they (students) don't know how to treat (and may not have the medications for). Better for the students to be at home with families when possible and the ones who must stay in the dorms can be watched over more easily. While our government could force a quarantine like China did, the leadership understands it is better for the citizens to do this themselves, through local/state, organizations, businesses, etc.
As far as it being worse than China, only time will tell but it is unlikely since the Chinese population is much older less healthy respiratory wise due to increased levels of smoking in the population (both past and present).
This virus is going to go through 20+% of the US population regardless of isolation. The key is to slow the rate of this spread, not the actual percentage. By slowing the rate, the cases are across a longer period of time, which improves the survival rate by not overwhelming medical community. We do not have enough hospital beds, respiratory equipment, personnel to care for the approximately 9 million who will need hospitalization.