...so you are not critically thinking about your work in the context of how useful it is to the end user? That's a bad UI work, I'd say.

As for your senior thesis - Developer's job is to create software that makes lives easier. It was your decision to use your skills to harm people by exploiting their privacy. Or it could be seen as something good - you discovered a way to exploit people and if you informed whoever was running this app you helped a good amount of people in your school.