> the idea that renting out a property for a non infinite period of time should be impossible is ??? to me
Nobody proposed that, especially for individual landlords with one property. However they do propose that a tenant can stay if there's literally no reason why not. Protecting tenants from unreasonable treatment, just like you have to make sure the electricity is safe, mould won't give them lung damage, roof doesn't leak, windows aren't broken etc.
> I think one should absolutely be able rent out a flat for a year whilst working abroad. Or to rent out a house whilst saving up to renovate and move in.
Under proposals I'm aware of, nothing would stop you renting out your flat for a year, or while saving to renovate. You aren't running a long-term housing business. You have a good reason.
Section 21 is when there's no justifiable reason. "The landlord doesn't like men who wear earrings / how you position the sofa / that you bring a girlfriend over at night / that you put up a shelf / you don't dust twice a week" type reasons, obviously not said or written.
Some landlords kick people out who ask for essential repairs (despite those being covered by the tenancy), as a sibling commenter said. Some corporate landlords want a certain "look" for the type of people in the property. Credit rating dropped? Getting old? Goodbye.
Try to think of older people who are settled and would buy if they could, forced to move every few years, have few choices locally, and daren't decorate and repair as they would like.
For some it means moving children to a different school where they lose friends and perhaps can't continue a key subject. Or moving far from their elderly parent's home, as I said. They can't lay "roots" in the community. And for the lower paid, moving costs months of discretionary income. That sort of thing is a huge issue and stressor.
Those burdens should only be imposed when there's a good enough reason.
> But actually 2 months has never been a huge issue when i've been renting,
It's not about the notice period. It's about being made to move, yet again, for no good reason. Summed up as "security of tenure".
(That said, in my experience it can take longer than 3 months to find a suitable new place. Once I was technically homeless (couch surfing) for a couple of months while hunting. I had the benefit of being single; imagine that with a family. In one town it took 35 viewings to find somewhere, and a lot of time off work. Many times I accepted a place, only to see it go to someone else who beat me to it.)
AirBnB is fine, if you can handle the work (it's hard work). Your wealthy guests will happily choose somewhere else if you run it badly. However if you want to run a business providing long-term housing to people who need it, there are standards.