In order for society to work, it cannot be segregated. High rent is the number one cause of segregation. For pretty soon the person who works and a restaurant, a barber shop, or department store cannot live near their work. They are stuck in the outskirts of these neighborhoods and never interacting with people with higher income unless they serve them. This makes it more of a class system than a fair and equal society.
Everyone deserves affordable housing. People should not be fored to pay high prices for tiny aparments. SIlcon Valley is a great example of what can go horribly wrong when the housing market is left unregulated. Rent control, like they have in New York, helps keep unscrupulous landlords from increasing prices just because they can.
In some areas of the country, rent prices need to be regulated. If this doesn't occur, most middle class citizens will not be able to find a place to rent. Space is limited, and landlords are greedy, so they will just keep raising rents higher and higher. Some regulation is needed due to people's greed.
New York has been offering rent control on their lower income housing projects for decades now and the results have been mixed at best. On one hand, it does keep the rent low and affordable, but at the cost of maintenance to the buildings, leading to sickness, unhappiness, and anger.