I think that this is 6 of one, and half a dozen of the other.
No, your DH shouldn't have to just sit there whilst your DS throws shoes at him - that just isn't acceptable.
However, neither is it acceptable for your DH to taunt your DS with things that he knows will trigger a meltdown.
But it's also not acceptable for you to just totally ignore your DS's violence.
There needs to be some element of avoiding triggers, some element of accepting that your DS will likely resort to violence when triggered, some element of getting across that violence is NEVER acceptable, some element if punishment FOR violence.
Basically, you all need to put some work in! 
I think you need to set rules with your DS that violence will NOT be tolerated, and if your DS is violent, he will lose (insert most loved thing here, needs to be motivating enough to make him want to stop).
I think you need to talk to your DH and tell him that it is not acceptable to CAUSE a meltdown.
I think you need to see that you aren't helping your DS in the long run by getting everyone in the house to tiptoe around him, because he will expect everyone in the outside world to do that too.
I hope you can all work together to manage these situations better. (((Hugs)))