Hey @Jjlasne. I'm replying here not as a representative of the team who built this function (I can take no credit for the tool, which I've never worked on), but as an administrator of mediawiki.org.
I see that you've never written on any talk page on English Wikipedia or French Wikipedia, the two Wikipedias where your user has been active, so I'd like to point you to civility as one of the core pillars of Wikipedia. People need to be able to disagree and talk to each other without every disagreement turning into an ugly conflict. Calling others "fucking morons" is pretty far outside (see Code of Conduct).
(As for the reason: The Wikipedia editing communities have been concerned about users not checking their translation, but posting substandard machine translations. This adds a significant burden on people who spend their spare time trying to clean up the wikis from spam, vandalism and mistakes. While I'm sure this is frustrating, this solution has been put into place because the alternative has been considered worse by the people who have to deal with the effects of the tool – it's there because it addresses a different problem, and there's no magical solution which will always work perfectly. In the best of worlds, people wouldn't just go ahead and post unchecked, unedited machine translations, and this would be unnecessary. However, that's not the world we live in.)