The key problem here is that it’s not just Walz making a singular mistake; it’s that his whole administration is illegally failing adequately safeguard information and illegally avoiding communications channels with official archiving capabilities built into them
This isn’t even an issue of legality in Trump’s world. Trump is upset that Waltz has the number of a journalist that Trump doesn’t like, which apparently is an indication of disloyalty. So it’s still weird that he hasn’t just fired the man