I wouldn't consider the original wording unacceptable but I would suggest leaning more towards the phrasing foobazgt used a few replies back. Specifically, claiming that X broke Y is likely not fact-based. The facts in such a situation are often: a certain test started breaking in a certain build and the build reports that only one commit is different than the previous build. I would suggest stating that fact instead of inferring that the commit was the reason the build broke. I've seen plenty of instances where it turned out that wasn't the problem. The build infrastructure itself was changed. The reported set of commits versus the previous build was inaccurate. The test was flaky. A third party dependency that the build system didn't insulate itself from was updated. The list goes on.
Allowing for the possibility that we are wrong isn't professional only because it is nice. It is also professional because it is honest and it helps focus the whole team on the facts so that we don't spend our time investigating the wrong thing.
