First of all, defecating is not a "sexual action".
Well, maybe for some people it can be, but for the majority of us it's just the means by which the body naturally evacuates solid waste.
Nothing sexual, nothing inappropriate, nothing inherently "dirty".
As you say, only to a pervert is it sexual.
But beyond that, what difference does it make whether we're talking about sex or not?
It's just "basic mammalian functioning", right?
Why are some perfectly normal and natural behaviors, having sex or relieving one's self as examples, "inappropriate" while other equally normal and natural behavior is perfectly appropriate?
Your misunderstanding the point of saying it's "not sexual" or a "natural human function"... do you think we don't know that some are inappropriate? Your not some genius that is brilliantly coming up with the contradiction... they are simply words to describe why Breast-feeding is different.
The most common reason why breast-feeding in public is considered distasteful is because breasts are uncharacteristically depicted as sexual, even when they are being used in a none-sexual way.
Defecating in public is DIFFERENT, there is a reason we don't defecate is public, we have bathrooms to dispose of the waste, we don't want poop or piss everywhere, and many want their privacy for their own genitalia
Your'e allowed to be nude in public dressing areas, because you are doing a function that requires you to be nude...
... all these things are unique and different to the situation... so I would put a halt to your black and white thinking... Breasts, by themselves, are not-offensive... they're sole function is to give a baby milk... so when they are doing their sole function, IT SHOULDN"T BE A PROBLEM....there are ways to display your breasts inappropriately, if you do it in an intentionally sexual manner. Same with exposing anything, their is NO reason for you to flop your penis out, zero... it's a sexual organ, it's only used for sex and peeing, BOTH are supposed to be private. Breasts ARE NOT!!! They have a function that is NOT sexual...
And if you say breasts attract men and make men think bad things...SO DOES EVERY PART OF THE WOMANS BODY... You are thinking like a hardcore muslim in that way... COVER HER FACE BECAUSE I WANT TO F%^& IT AND I CAN'T CONTROL MYSELF...
You can control yourself, and you can realize what is a natural human function AND Not-sexual AND not something to be uncomfortable/shamed by...