Funnily enough, that episode provides supporting evidence:

BASHIR: Starfleet Medical won’t see it that way. DNA resequencing for any reason other than repairing serious birth defects is illegal. Any genetically enhanced human being is barred from serving in Starfleet or practising medicine.

One has to conclude that the procedure Bashir underwent is considered an enhancement, not a “repair” - like they tried to overcome his undefined disability through brute force, rather than address the underlying cause.