Wow, you're a stroppy one! Do I gather that you've stormed off now?
Anyway, in case you haven't, one last time...
If you think baths are ok (some people don't, which is a more logical position to start from) then they must serve some cleaning purpose. You're going to be cleaner if not 100% bacteria-free when you emerge.
The more water you use, the cleaner you'll be.
The less dirty you are to begin with, the cleaner you'll get.
The better you wash, the cleaner you'll be.
As you can see, there are various factors at work. And certainly, the addition of another person is going to tip the effectiveness towards the 'less effective' end of the spectrum.
BUT it doesn't follow that the addition of another person is automatically, universally where it changes from 'fine' to 'disgusting'. Youfeel this way - but that is not scientific fact. It is not fact of any sort. It is your opinion.
Of course you're entitled to that opinion. I'm I'm entitled to think that going on and on about that opinion, when the OP jas clearly stated that she does share baths, is just rude. Hence I called you out on it.
You seem to think I've 'name-called'. Well, I think you have been ruder, because you (and others) have essentially called the OP and others who do likewise 'disgusting'.
For the last time, it's not 'disgusting' by some objective margin. Some people are squeamish about it. That is all.