I have gotten that reaction before as well when I didnt receive an email. Why is it invalidating to say your sorry, you didnt get the email or something like that. I have never understood why I end up with a few hours of being ignored after I say that.
It is invalidating because you they are feeling hurt or upset.
Their feeling is a real legitimate feeling. Nothing about the feeling itself is wrong.
The invalidation is that you are telling them they shouldn't have that feeling.
A good validating response would address their feeling, and explain how you understand how hurt (or scared or angry, etc) they are feeling.
If you point out how your action wasn't supposed to bring out that feeling, that doesn't help their feelings in any way.
Note: I'm not saying that the rage/silent treatment/whatever which follows is justified. Just that the feeling is real and validating the feeling helps the situation!