Since when do people that own things have a moral obligation to justify their prices?

>It is the market's prerogative to demand justification for a seller's price.

Bollocks. It's the market's perogative to meet that price or not meet that price.

It is the market's prerogative to do whatever it wishes, including demanding more information before transacting.

I think it's pretty clear in this situation that the justification is "We don't want to rent our house to you anymore so we are raising the price to a point where you will move out."

When the girl across the bar holds eye contact with you for a couple of seconds and then looks down and away she wants you to come talk to her.

Not everything is always stated in black and white.

When dealing with real transactions, every thing should be stated in black and white.

Hah yes. I almost didn't leave this comment due to tempting that other flame war. But it was the best example I could think of off the top of my head of an unstated but clear communication.

I am not completely familiar with SF's laws, but typically rent-control laws state that an owner may only evict a tenant for good cause and that leases are otherwise indefinite, at the tenant's discretion.

In this case, the owner has evaded rent-control to extrajudicially evict the tenant through extortionist pricing.

Why are leases otherwise indefinite?

1) Because that is generally the law. Typically with a 30 day notice of termination required from the tenant.

2) The reason for the law is that people should not be thrown out of their homes on the whims of a second or third party.

The law as it pertains to these contracts or all residential tenancy contracts in the US?

Are 3-, 6- and 12-month leases common? All the residential arrangements I know of here in Australia would be 6- or 12-monthly. Gives a tenant some certainty, but also enables a property owner to move back in, sell, redevelop, etc.

The law as it pertains to rent-controlled jurisdictions.

All lengths are common, though 12-month is perhaps the most common. In rent-controlled jurisdictions, when a lease expires it converts to a month-to-month tenancy where the owner may only evict for good cause (failure to pay rent, gross negligence, illegal activities, etc), but a tenant must provide 30 days notice of intent to abandon.

Often an owner is allowed to require a lease extension be signed, only if the extended lease is materially identical to the current lease except in expiration date (including length of the lease).

Almost everywhere in the US the standard is 12 month leases. Sometimes a landlord will do a 6 month lease. When these leases lapse (or if no lease was signed), the relationship is governed by landlord-tenant law, which usually states that the landlord must provide 14 or 30 days of notice when removing a month-to-month tenant.

I'm not very familiar with rent control practices, but in 99.9% of the US, this thing where the tenant is allowed to indefinitely block the usage of your own home is not done.