Cyclists are generally traveling from point A to point B whereas the sidewalk is for:

• groups of people standing still talking/looking at phones/scamming tourists/taking photos
• food carts / news stands / those folding table "vendors" reselling stolen goods from CVS
• that extra doorway restaurants construct every winter
• outdoor seating for restaurants
• dogs
• sleeping people / people who took too much drugs and need to rest it off
• bus stops
• covid testing tents
• subway entrances
• dogshit
• police vehicle parking
• children playing / running / and even riding bicycles if they're 12 or under
• food delivery people riding full-blown motorized vehicles
• giant piles of garbage