OP 'am I being unreasonable?'
Most replies 'yes'
Response 'you're all horrible and have no standards'
I know you were upset by my previous comments about not being suited to be a landlady. That isn't nasty, it's realistic, most people aren't. I had to move around lots for years due to work, house shares and lodging. You very quickly realise that what is 'common sense' for one person isn't for another, and it's actually just different ways of living.
As someone else mentioned, I leave clothes in the drum - because I put them on when I go to work. I dry washing in my room - habit, to keep them out of other people's way, and not having space. I do now have a yard but wouldn't dry outside due to having bad hay fever (and a neighbour who likes random bonfires) I do open a window of I'm home but shut it if I'm out for security.
All of those things to me are common sense, but to you would be interpreted as low standards. They aren't though - they're just different. And accepting those differences is necessary if you want to make money from renting out a room. If you find it really hard to accept differences like that, as many people do, then it's not well suited.
In my years of sharing space I had to deal with people selling furniture that came with the property, people inviting randoms over, someone who cut the wiring to all our electrics (paranoia) someone growing weed in the wardrobe, men who rented single rooms who had declined to share they expected their kids to sleep over, a landlady who threw out anything in the kitchen she decided was junk, regardless of who it might belong to, a landlady who invited half her family to stay from abroad for three months, someone who regularly left the oven on at night after making late dinners after their shift, someone who kept putting the alarm on in the day when I worked nights... If putting clothes on a dryer in his room is the worst thing this lodger has done, I think you should count your blessings.
These were all in 'professional' house shares btw, not in student accommodation.