No, Kobe Bryant Day should be a day hosted by Los Angeles. Kobe Bryant was a dynamic athlete in the city that helped bring numerous championships to the area. These championships mended a community, brought people closer, and increased revenues. His role in the community as a volunteer, role model, and public icon has helped kids better their lives, find something / someone to look up to, and provide a motivating force they strive to be. The day is justified because he made the area a better place.
Kobe Bryant is one of the greatest basketball stars of all time so why would you not honor him. He changed the sport in a good way and changed the way Los Angeles looks at the Lakers. Honoring him is the least the city of Los Angeles can do to for his success.
Some sports stars have done a lot for their communities, and Bryant may be one of them. I don't know about his charitable donations, but he's probably been involved in a number of things. He's getting involved in global investment funds, and he's played for the Lakers for 20 seasons, so it's not like he's been there for a month.
Kobe Bryant Day is not too high an honor for a sports star when one steps back to consider what this man has meant to the city. Not only in the form of recognition, but more importantly, the amount of money he has generated for the city. Stop complaining and enjoy the day.