Over the years I have had to scrub dog shit out of a long hall carpet, try to remove ground in dirt that had been walked in from underneath the decking, anyone that has ever seen 20 year old muck from under decking will understand the power it has to adhere, scrape chewing gum out of a mat, and try to remove car oil from stair carpet and a bedroom.Then there was the bird poo that was walked in.
Of course those who think it is precious to remove shoes may not have carpets, but in rentals you don't have a choice. You also have to consider bringing in the remains of spittle and snot from those charmers that spit on the pavements and blow their nose without a handkerchief, on to the ground, vomit and human excrement and pee, all of which gets trodden in and spread liberally around so that there are traces of it a distance from where it was deposited.
So, yes I do ask for shoes to be removed upstairs regardless and downstairs if I consider it necessary, although it is easier to clean a wooden floor. Not so good when stiletto heels leave little pits in the wood though, so having realised too late about that, they have to come off now.
I respect the wishes of others, they may want a germ free home because of illnesses or religion, and I prefer not to wear shoes indoors anyway.