You don't.

This is unavoidabe. If the system requires the students to collect X credits, but they are only interested in courses totaling Y < X credits, they will take X - Y worth of courses solely to get the credits.

There is nothing wrong with this. The student will take courses they wouldn't choose on their own, which will expand their knowledge in other directions than their main interest. They may find it more interesting than they initially thought, and focus on the topic more in the future.

And it might have impacted my grading for that student. [...] Should I ask them to drop the course?

I find this statement very concerning. You openly admit to have a big negative bias on the student as if it was a natural thing. It is not. Not only is it a serious misconduct, but it is totally uncalled for. The reason for the student taking the course is totally irrelevant for their grades, and does not reflect their work at all. Frankly, this have been the introductory lesson, and you are already deciding on lowering their grades. Please, grade the students fairly, based on their performance, and not on your prejudgement.

Depending on the way you "chewed" the student, I would also be concerned about the student sensing your negative bias. This could reflect on your student ratings and may also reach the dean as a complaint if the student feels discriminated or harrassed. The other students may also be repelled by your reaction. I'd suggest that you may want to sort this out.

You don't.

This is unavoidable. If the system requires the students to collect X credits, but they are only interested in courses totaling Y < X credits, they will take X - Y worth of courses solely to get the credits.

There is nothing wrong with this. The student will take courses they wouldn't choose on their own, which will expand their knowledge in other directions than their main interest. They may find it more interesting than they initially thought, and focus on the topic more in the future.

And it might have impacted my grading for that student. [...] Should I ask them to drop the course?

I find this statement very concerning. You openly admit to have a big negative bias on the student as if it was a natural thing. It is not. Not only is it a serious misconduct, but it is totally uncalled for. The reason for the student taking the course is totally irrelevant for their grades, and does not reflect their work at all. Frankly, this have been the introductory lesson, and you are already deciding on lowering their grades. Please, grade the students fairly, based on their performance, and not on your prejudgement.

Depending on the way you "chewed" the student, I would also be concerned about the student sensing your negative bias. This could reflect on your student ratings and may also reach the dean as a complaint if the student feels discriminated or harassed. The other students may also be repelled by your reaction. I'd suggest that you may want to sort this out.

You don't.

This is unavoidabe. If the system requires the students to collect X credits, but they are only interested in courses totaling Y < X credits, they will take X - Y worth of courses solely to get the credits.

There is nothing wrong with this. The student will take courses they wouldn't choose on their own, which will expand their knowledge in other directions than their main interest. They may find it more interesting than they initially thought, and focus on the topic more in the future.

And it might have impacted my grading for that student. [...] Should I ask them to drop the course?

I find this statement very concerning. You openly admit to have a big negative bias on the student as if it was a natural thing. It is not. Not only is it a serious misconduct, but it is totally uncalled for. The reason for the student taking the course is totally irrelevant for their grades, and does not reflect their work at all. Frankly, this have been the introductory lesson, and you are already deciding on lowering their grades. Please, grade the students fairly, based on their performance, and not on your prejudgement.

Depending on the way you "chewed" the student, I would also be concerned about the student sensing your negative bias. This could reflect on your student ratings and may also reach the dean as a complaint if the student feels discriminated or harrassed. I'd suggest that you may want to sort this out with the student.

You don't.

This is unavoidabe. If the system requires the students to collect X credits, but they are only interested in courses totaling Y < X credits, they will take X - Y worth of courses solely to get the credits.

There is nothing wrong with this. The student will take courses they wouldn't choose on their own, which will expand their knowledge in other directions than their main interest. They may find it more interesting than they initially thought, and focus on the topic more in the future.

And it might have impacted my grading for that student. [...] Should I ask them to drop the course?

I find this statement very concerning. You openly admit to have a big negative bias on the student as if it was a natural thing. It is not. Not only is it a serious misconduct, but it is totally uncalled for. The reason for the student taking the course is totally irrelevant for their grades, and does not reflect their work at all. Frankly, this have been the introductory lesson, and you are already deciding on lowering their grades. Please, grade the students fairly, based on their performance, and not on your prejudgement.

Depending on the way you "chewed" the student, I would also be concerned about the student sensing your negative bias. This could reflect on your student ratings and may also reach the dean as a complaint if the student feels discriminated or harrassed. The other students may also be repelled by your reaction. I'd suggest that you may want to sort this out.