The 2009 law said that someone who gets the property on the courthouse steps (the bank, an investor, FannieMae) has specific requirements in how they treat the tenant.
They are required to either respect the existing lease (by creating an identical lease with their name) or to give a 90 days notice to vacate to the tenant.
There is no provision to charge those tenants rent during the 90 days (its not quite that simple but that’s what it boils down to).
That is why every bank pays giant scary law firms (like Wolfram & Hart or Pite Duncan or Morrison Forrester) to offer a contract to decide if the tenant wants 90 days or $5000 to move out in a few weeks.
This law does not extend to former owners, but usually a bank does not care that much who is occupying and will treat any occupant as a bona fide tenant.
The Realtor-Investor-Landlord-Douchbags obviously have not researched this at all and are trying to intimidate the tenants.
And yes, I know that Wolfram and Hart is not real.