“is that a reason to fail to encourage, through public discussion, proper mitzvah observance – be it Shabbos (which won’t bring out the naysayers) or be it tznius (which will)?”
Joseph,
IMO, yes. When a sincere person begins a public discussion on improvement in a specific area, and instead of bringing like-minded people to the table to brainstorm on how to improve general awareness and greater appreciation for the mitzva, it serves as a magnet for mocking, trivializing, and elaboration on why it’s NOT a worthy area in which to improve, others read and are inevitably impacted. It doesn’t bring Kiddush Hashem, it brings negative vibes on the Mitzvah.