He took 3 steps, made a "football move" (by reaching for the end zone) Bad call. Catch all the way. Not only should it have been a catch, it should have been a TD
He was going to the ground. By the rules if you jump to make a catch, you have to secure it if you go to the ground.
You can argue with that all you want, but its the rule.
So technically its a good. Now you can argue its a bad rule.