Simple is the opposite of complex, not the opposite of hard. Saying something is simple has meaning, and it's not insulting.
If my docs might be used by a new programmer I try to avoid alienating my users with the word simple.
But it's a rhetorical question...
Feeling offended is a very different emotion than feeling alienated.
...yes it is? The word has multiple meanings.
> free from complexity or difficulty [https://www.merriam-webster.com/dictionary/simple]
> involving minimal difficulty or effort [https://www.merriam-webster.com/thesaurus/simple]
etc
Words should be used carefully or we end up with no word to say what we mean. That's why there's literally no word meaning what we want to say by "literally".
But from context you can determine whether "literally" means "literally" or "figuratively". It's the same with "simple", you should assume it means "simple" and not "easy" in the case of a documentation where words are chosen carefully.