[keepper]

What you just described is an issue with every toilet seat... it is not unique to bidets.

What I think you mean is that the sprayer/nozzle can get dirty? Do you have similar fears of your kitchen/bathroom faucet? because there's no way anything can stay in the spray nozzle of a bidet. that part self cleans instantaneously.

[sgc]

I don't try to clean myself with my toilet seat. It might "self clean" with water, but that is far from sterile. And yes of course a sink used to wash after using the toilet is dirty, as are the towels used to dry your hands. After a year of a pandemic, we should know that none of this is perfect. As in many cultures, we use separate towels for hand wiping and face wiping for this very reason.