It's a pattern seen in many neighborhoods (see Flushing's Cherry Ave) where landlords ignore law and safety for greed or at least the means to pay off a high mortgage. The NY Times gives detail on the pervasive problem of illegal conversions in Queens:
According to city records, 70 percent of all complaints citywide to the Buildings Department about illegal conversions since 1999 have involved houses in Queens. Complaints about illegal conversions citywide have increased to 23,393 in 2005 from 6,064 in 1999.70 percent! The overcrowding complaints from Queens are more than double those of all the other boroughs. The reason is that Queens has a high number of immigrants working low-paying jobs and plenty of large one-family homes in neighborhoods along good subway and bus lines.
"You don't move in thinking bad things are going to happen," said Ivan, who did chores at the burned-out home in exchange for rent and who declined to give his last name. "We're just trying to move ahead and have nowhere else to stay."