He wasn't disciplined for building an app or fetching data.
He was disciplined for blatantly trying to "hack" (in the YC sense, in UW's view) the registration process:
https://registrar.washington.edu/winter-2025-registration-ch...
"Know that trading, selling, or buying open spots is a breach of the Registration Tampering Abuse Policy. Consequences include referral to the Student Code of Conduct process, a Registrar’s Hold on your record, and potential diploma withholding for graduating students until the conduct process is complete."
https://registrar.washington.edu/registration/policies-proce...
"Registration Abuse
The registration system is provided for the sole express purpose for students to register themselves into sections. Any use of the registration system other than for this purpose is considered abuse of the system. Such abuse includes, but is not limited to, buying or selling one’s seat in a class, holding seats for another student, or otherwise registering for a section that one has no intention of taking."
Disclaimer: I am making no claim about the ethical validity of this policy, and I don't know how well the policy is communicated to students. I am not commenting on the allegation that the University demanded free labor in exchange for not-expelling OP.