Is seeking guidance for women who are immodestly dressed an act of disobedience, in violation of the the command of the Messenger of Allah, peace and blessings be upon him?

Seeking guidance for immodestly dressed women or other sinners is an act of devotion for which the doer is rewarded, whether through guidance and admonition or by supplicating for them. It is not permissible to curse a specific person, but it is permissible to curse a general category, such as Allah's cursing of oppressors, disbelievers, and liars.