It's too bad this lawsuit didn't make it into court. It would have been interesting to see how it would have turned out.
But, it is expensive to participate in a case that is not being tried in your local area; it means legal expenses, hotels, meals, and travel expenses, etc. If the trial had been delayed, for some reason, the defendant in the case would have had to do it all over again, adding to the expense. The settlement probably cost him less than it would have cost him had he won in court. Often the plaintiff in such a case will depend on that happening.
In this country, it is not considered libel or slander if you can prove that what you said is true. If you can't provide proof, then you have a problem if it goes to court.
I can't think or any organized group here that would have helped him to defend himself to avoid precedent being set. We do have a very excellent organization, the American Civil Liberties Union (ACLU) who would, (had he defended and lost), then challenge the law on constitutional grounds if it seemed appropriate.
As for Microsoft, I guess they are so big and arrogant that they probably figure you can say what you want, but in the end you will still buy their product. Most people do.