Are all landlords insane? Can collecting rent ever be perceived to be the right thing to do?

Yes they are. Obviously, collecting rent is extortion, nearly everybody understands this fact.

Why is it insane?  If you own a house and you want to rent it out, you have that right. Collecting rent is hardly crazy--it's just another way of living. 

Are all landlords insane? - not in the slightest. Any I wonder why you think they are. Private landlords are providing a service. They can offer you a home when there is little public sector housing available, and they can offer you a home when you aren't in a position to buy your own place.

Can collecting rent ever be perceived to be the right thing to do? - so, do you think they should go to the considerable expense of purchasing a property and maintaining it, and let the likes of you live there for free?? Really? Sorry, Simon, but only your mum is going to let you live anywhere for free!

When was the last time ( or ever) did you go to the supermarket and help yourself to the goods, or go and take a car for yourself for free? Being a landlord is a business, so rent is their wage...... so if you think everything is free in the world you are either a child or very immature and have no clue about working, earning and paying for what you use/get

If they didn't collect rent, then anyone who couldn't afford to buy a home would be homeless.

Nobody is going to let you live somewhere for free. 

Collecting rent is wrong?  So, you should get to live in someone else's house for free?

Yeah. I'm insane for not supporting my tenants by allowing them to live in my property for free.  [/sarcasm]