Bidet is so convenient, quick, effective, easy to install, cheap. Only thing I miss on cruise ships is bidet.
Most people don't have bidets, but it's easy to shower after defecation. The cosmetic effects alone are worth it. The detrimental public health effects of not washing are comparable to not washing the hands after defecation.
I'm a physician. I'm sure this affects my judgment in this matter, but washing the perineum after defecation is as important as washing hands--and certainly before entering a swimming pool.
If thinking about this gives people the creeps, that's a good thing. Maybe it will inspire better hygiene.