If the mother has passed on, you have every opportunity now, if it is true that you are the 'good guy' to show this to the children. If truly what you say is correct than all would come to light in time. but unfortunately I fail to see that helping your children was the motive in this.

To be honest, it seems to me something has been left out. It seems to me you talk about how you were trying ot point out the failings of the mother, but leave out the context to which this conversation occurred. I would guess that this happened in the midst of an argument where you felt like you were being criticized, probably by the child or children and this was your reaction, by bashing or as you put it pointing out the failings of the mother.

Seems that this was more than likely in defense of yourself more than it was in a way to help your children somehow. How is telling your child that their mother failed them at all going to help them anyway?

The reaction as most people here have agreed with is actually pretty understandable and even acceptable if the passing of the mother were as recent as we assume here, in fact even if it weren't recent most children will react similarly.