Housing laws are complex and weird and in many cases laws are based on case precedent or specific things happening in an area. They vary greatly from state to state and often include archaic provisions. They also don’t garner a ton of attention from the media, so things sometimes get passed in large bills that are weird one-offs because someone who’s involved in voting on the bill who was important asks for or inserts something due to a particular bias or belief.
Arbitrary Lines is a good, basic primer to the subject and has a bunch of examples/case studies to this end. a lot of modern city zoning–although this might not be true in this case–is just a vast accumulation of exemptions and changes to accommodate one specific property or building with no particular rhyme or reason other than “this was needed to fulfill the intended development at the time”