I think if I got mud on, say, my inner thigh, I'd still want to clean it off. With water.

If I was, say, playing football with friends, and somehow got mud on my inner thigh, I might wipe it off with paper, and then later take a shower.

I might use just paper if water wasn't available, sure. But I'd certainly use water if I had the choice.

You've used correct logic but you missed the point OP was trying to convey.

What did I miss? OP is arguing that we should wash our behinds for the same reason that we wash our hands. Yet the reason we wash our hands is to reduce a threat that does not exist (at least, not as readily) for our behinds.

And now semantic satiation has kicked in for "behind."

>What did I miss? OP is arguing that we should wash our behinds for the same reason that we wash our hands.

No. OP is not arguing that. OP is arguing that if you got mud on your hand and tried to clean it with dry paper, there will still be crusted mud on your hand. Do you see where this is going now?

OP simply doesn't say that. OP refers to the actual common act of washing hands after using the toilet, not the hypothetical act of washing hands after getting "mud" on them.

I think OP meant that washing is good for personal hygiene i.e. not carrying pathogens smeared around on your skin/clothes.

That's a valid point, but not one that directly supports the argument for bidets. Since most people (at least in my neck of the woods) shower at least once a day, personal hygiene is usually accomplished.

So personal hygiene is a no-no until you can prove that you can get sick?