What would be a good thesis for a persuasive about how the dresscode ...?

Question

has gotten ridiculously strict this year at my highschool.

Answer 1

Perhaps:
The changes made in the dress code this year are too strict, causing students to lose a sense of individuality, be unable to wear many of the clothes they own, and be forced to scrimp in order to try to find funds for clothes that do meet the too-rigid restrictions.