I know the Italian proverb Traduttore traditore very well as I have been working for a major international translation organization as a linguistic consultant for many years. While the proverb is often misunderstood as disparaging the work of translators and interpreters, it can just as well be taken as a criticism of popular misunderstandings of what translation means - as you, Danielle, seem to have tried to show with your English-French examples.
But look at it this way: When two people with different mothertongues try to communicate, translation is inevitable. If a "common language" is prescribed for communication, it forces everyone, whose mothertongue is a different language, to translate what they want to say into that language, resulting in "treacherous expressions" even before an interpretation of that person‘s statements has been done. This is what currently happens at WikiTree: many people feel that they have to communicate in English, i.e. every non-English speaker is disadvantaged here. By contrast, if everyone could use their own preferred language, then every speaker / writer would feel comfortable in expressing themselves, and the disadvantage of "treacherous translation" would be evenly distributed across all listeners / readers, regardless of their mothertongue. For example, an originally Spanish statement could then be translated into German, French, Tagalog, Afrikaans, etc. with the help of automatic translation which is sufficient to get the general gist.
Now, for literary translation, e.g. of the Bible, or of other works of art like Lord of the Rings, I would never suggest automatic translation. However, for everyday human interaction like we have among genealogists on this forum, we do not need the high standards of literary translation.