How does this happen to a professional basketball team?

In the throws of blowing a 25 point lead including allowing a 20-0 run in the last 6:22 of the fourth quarter, the Hornets found time to forget what basket they were defending and allow Kobe to streak uncontested for a dunk that put the game out of reach.  How, with 24 seconds left in a 2 point game, does a team forget what basket they are defending?  Hopefully the name change to the Pelicans next season can erase the Hornets' recent misfortunes.

PS Kobe ended last night with 42 points on 14-21 from the field with 12 assists and 7 boards.  Here come the Lakers.