Axelrod is a tactician above all else, and he knows this will make things worse for Democrats in the long run, not better. It's a simple calculation for him. His is not any sort of commentary on the quality of job he thinks Trump is doing, just whether or not such a move moves the ball down the field for his team, and he has concluded it does not.
This is why I'm tempted to cheer for the Maxine Waters of the world, who want to take Trump out by any means necessary.