I realized some of the questions they had asked me were discriminatory to my medical condition regarding my previous studies at university.
Because I wrote in the application that either I have some college done or that I have attended college, I was asked if I am done with school at a 4 year university, to which I responded to with "no, I've got 2 more years left."
At some point I mentioned that I've learned that I have to either study full-time or work full-time, but not both at the same time. I also did mention that I need to work full-time for health insurance, even if it means working in leadership (that I'm willing to do anything to work full-time when school is not in session and take a leave of absence for when school is session until I receive my degree. This is regardless of if benefits apply when on leave).
Then I was asked if I study full-time or part-time, in that order. I responded with "I study full-time, but with the minimal amount of units required for full-time," finding out that the interviewer both works and studies full-time.
Then I was asked how many units I take, telling them "13 units." Next, if 13 units is 4 classes, responding with "no. It is 3 classes."
Based on what you wrote, there doesn't seem to be any discrimination.
I think that you got turned down because some of your responses were not the best things to say during the interview.
You told them that "[you] 'need' to work full-time." However, the store can't guarantee a set number of hours since payroll is not constant. If you were not okay with hours fluctuating from week to week, then you wouldn't get the job. Unfortunately, that is the way that it works in retail.
You told them that you need this job "for health insurance" which is a no-no because it doesn't sound like you were truly interested in working for Target. Interviewers aren't oblivious; they know that people want a job for the money, benefits, etc. However, you shouldn't say it during an interview. Also, store interviewers don't turn people down because people would need to enroll in health insurance if they get hired. Most of Target's benefit processes are not even handled at the store-level (nor affects the store) so it is not really a factor that interviewers would care about when considering applicants for a job.
You said that "[you have] learned that [you] have to either study full-time
or work full-time, but not both at the same time." This shows that you can't handle multi-tasking which is an important skill for many positions. I am not denying that going to school full-time
and working full-time at the same time is hard to do. However, the way you said it probably worked against you.
You said, "even if it means working in leadership (that [you're] willing to do anything to work full-time when school is not in session and take a leave of absence for when school is session until [you] receive [your] degree." This means that they will need to hire a replacement again really soon for the 9+ months that you will be gone out of the year. The educational leave thing might work if you have already proved yourself and they would be more than happy to have you back to help out during the busy seasons. However, interviewers try to hire people who can work year-round despite having school.
Also, the "even if it means working in leadership (that [you're] willing to do anything to work full-time" thing probably sounded a little too desperate (sorry, just giving you honest feedback) for an interviewer who barely knows you. In addition, it pretty much guarantees that you won't be considered for a leader position. Why? You didn't sound truly interested in becoming a leader.