Eh. I think you're misreading this a bit - it's not about the use of the service, it's about the fact that employees knew the service was being used illegally. So sure, if the manufacturer can be demonstrated to be aiding criminal behavior, then sure.

The fact that a manufacturer doesn't sell direct is another reason to think there's no relation to this case.

Well if the employees manufacturing the guns take payments from criminals to alter the guns in some way to help them do bad things AND the gun company knows it, but ignores it then yes they should.

Given the direction of IoT devices, I hope the generic form (if the employees manufacturing the X take payments from criminals to alter the X in some way to help them do bad things AND the X company knows it, but ignores it then yes they should) of your statement is always true.

Store owners and employees are absolutely prosecuted if they fail to run background checks, or sell guns when they have even a suspicion that the buyer may be purchasing it for someone else, or intending to use the gun for illegal purposes. They're frequently audited, as well.

I do not think this is the correct analogy.

The analogy would be gun manufacturers helping customers avoiding detection after illegal usage of their weapon. In that case, yes. It's bad.

No. But, very possibly, those who sell guns should be penalized when those guns are used in an illegal manner - given due process, etc etc.