Sadly, the good doctor’s explanation was completely ass-backward–literally.
You see, any pathogens you are pooping out already made it past the “oral” part of the fecal-oral cycle. It’s the OTHER guy’s feces that might contain pathogens for you; if your own feces contains pathogens you are already infected and it’s too late.
Feel entirely free, medically-speaking, to munch your own fe…never mind; the thought is disgusting. Reminds me why I don’t like babies. In any case it is absolutely impossible to avoid the bacteria you carry around on and in your own body.
On edit: perhaps I read it too fast. If the good doctor is saying frequent hand washing avoids contamination from others…well; kinda. But it would have to be pretty darn OCD-level frequency. It’s really not very practical, although certainly a given public toilet, frequently-used enough to have viable bacteria everywhere, is a reasonable motivation to wash in case any pathogens were left by its filthy previous users.
I’ll summon up the ol’ ghost of Ignatz Semmelweis, who really didn’t get enough credit in his own lifetime with hand-washing hygiene, and had to fend for his very rational observance of bodily contamination against the mores of the day. Really, read the whole Wiki article, it’s worth it.
Those ideas were radical for the time, but are accepted as sound now. And, since it’s been a relatively recent development, only a hunnert and fifty years or so, right, I’d expect we’re right what we should be paying real attention as a group.