That's the topic of Gary Bernhardt's (of JS WAT and Execute Program fame) very important "A Case Study in Not Being A Jerk in Open Source". https://www.destroyallsoftware.com/blog/2018/a-case-study-in...
It absolutely looses some meaning and important information conveying, and most importantly some impact factor.
Communicating by pretending you are in a neutral state of mind when you feel very strongly about a subject put everybody at risk of not understanding the perceived importance of it.
The rewritten email looks like corporate bullshit and is the kind of thing you risk to immediately forget. It looks like The PowerPoint slide that crashed a space shuttle https://medium.com/@JoachimLasoen/the-powerpoint-slide-that-...
It would have been way less distributed and discussed if originally written this way.
Now the original is maybe too much and, while a few repetitions are ok, it contains probably way too many. But there is probably a middle ground to be found between the original email and the rewritten one. For example, "AND STANDARD" in caps is perfectly fine if you want such strong emphasis on that point. Likewise for "documented" for emphasis but somehow less than caps. That makes no sense to pretend that such emphasis is a meaningless expression of anger; those are key point of the mail, called early on. I agree you probably want to avoid "f*ckin moron" and "braindamage", however there is no point in removing "piece of garbage" about this point in the C standard, and the precise point being talked about is contextually clear in the mail.