Regardless of legality, this is obviously wrong. The owner of the property clearly has no understanding of reality; they're going to be financially destroyed by this move, so no additional action necessary on that front. Glad to see someone so evil fall on hard times; pity they won't suffer more.
As for the tenant(s); if you want to relocate, I'll put you up in Minneapolis for free for a couple months if you want. No conditions, just let me know.
From the records on Zillow, assuming they owned the unit free and clear, the landlord was likely losing money at the current rent: it's less than the current taxes on the unit.
Should they have been forced to continue to rent the unit out at a loss?
The tenant was paying $2,145/month = $25,470/year.
According to the letter, they forced out another tenant. IF that tenant was paying a similar amount, the landlord was making >4x taxes in rent, not less than the current taxes.
Also, the current owners bought the property on 12/30/2014. Why should anyone have sympathy for them having tenants? They knew they were buying a rent-controlled building. They aren't some owners for the past 30 years being held victim to tenants who won't move out.
correction to myself on "buying", it appears the previous owner was "SHUKRY & VERA LAMA RVC LVG TR" and the new owner is "LAMA NADIA V", so it probably was an inheritance, not a purchase.
If you read the facebook post, it claims they transferred the house from one couple to a sibling as part of the process that allowed them to increase rent.
As for the tenant(s); if you want to relocate, I'll put you up in Minneapolis for free for a couple months if you want. No conditions, just let me know.