His past was common knowledge
To whom? The people in the bursars office? Remember, community college = no admission department. On what source are you basing your assertion that someone "in charge" at Yale had any idea who had enrolled in these night classes in the first place?
I don't disagree that his presense in the US is poor. What I disagree with is holding some private institution liable for governmental immigration policy.
Why is it that you feel Yale has some responsibility that every other place Sayed goes does not? Where is your concern about his grocery store? Why no anger at his landlord? Cab service? Barber?
I'm sure you'd be the first in line pissing and moaning if any US institution barred someone you favor access, but somehow Yale's night school needs to be held to a standard that even the government doesn't have?
All you seem to be in favor of is prejudicial behavior on the part of private businesses toward individuals legally in the US. Whether this guy is unsavory or not is immaterial, because our right to privacy doesn't include Yale or anyone else even asking the questions you are demanding.
It is sick and unAmerican to expect, or even prefer, that businesses, institutions and professionals screen their clientel so they don't offend your sensibilities. It is little different than racial segregation, and our laws reflect that we believe such actions are a violation of civil rights.
Let me put it in a way that you might, somehow, understand:
If Yale did refuse admission based on Sayed's past beliefs and associations, they would be liable for lawsuit, which they would lose.