I feel that my flip flops are often far cleaner than my shoes. Sure, there might be a little dirt in there, but since when did a little dirt on one's feet kill someone?
In contrast, feet trapped in shoes smell more than flip flop ones. This is because all the sweat/dirt/etc gets trapped and builds up in there. They smell. They take more work to keep from smelling badly. Flip flips may get dirt prints, but they don't smell like shoes, there's probably dirt prints in many shoes out there too, you just don't see them. Most flip flops only last a season, so they don't get the years of build up.
All I need to do to clean my flip flops off is walk through a mostly water puddle. Or a hose. Or a lake or river. Or rains.
BAM! clean feet and flip flops. Do any of this in shoes and your feet are worse of than before.
Also, flip flops will never wear the skin off of the backs of my heals or toes.
There are less socks to put through the laundry at the end of the day.
Any fancy polish work to my toes gets to be shown off.
They're easy to throw on and off, into a bag, carry around etc.
They're cheap, and easy to match to anything casual.
In short: they're versitle, comfy, affordable, and probs cleaner than shoes.
Despite what you seem to think.
Whatever, haters gonna hate.
Or you've got a fear of feet.
Or maybe you should look up from the ground once in a while.
Or if you really just don't want to see feet, I'd really like to see some people walk around with bags over their heads 'cause I don't wanna see that either. But you ain't gonna see me complaining about it.