Most landlords arent big corporate in the USA either especially in areas where the housing crisis is the worst.
I think this narrative is just meant to distract people from questioning the necessity of the landlord class, they want people angry at a faceless corporate boogieman instead of local landlords (for obvious reasons)
Services like RealPage provide information that allows the small landlord to act like corporate overlords, praise be American corporatism.
Rental prices are set at the edge, so you only need to own a fraction of the market to drive rent increases. Corporate landlords absolutely do this.