Yup unconstitutional to give him a violation, let alone a driving ban based on that.
I wonder if there's any law firm who'll take up his case, but this seems like it should be slam dunk.
1987 Philippine Constitution - The LawPhil Project
Article III (Bill of Rights) Section 4: No law shall be passed abridging the freedom of speech, of expression, or of the press, or the right of the people peaceably to assemble and petition the government for redress of grievances.