In technical documentation, the author assumes the reader already knows what they're doing. It assumes prior knowledge on a subject. It assumes that just because one person considers a task trivial, that everyone else will too.
"Just" makes me feel like an idiot. "Just" presumes I come from a specific background, studied certain courses in university, am fluent in certain technologies, and have read all the right books, articles, and resources. "Just" is a dangerous word.
I feel the same about "Simply".
It first occurred to me how this sort of language is damaging when running a workshop for Sky a few years ago. Teaching can be challenging. You not only have to articulate how something works in order to teach it, but you also need to cater for the different skill levels and backgrounds of the audience. Words like "Simply" and "Just" are heavily overused in these scenarios, and you can quickly wind up in a situation where you've alienated your audience.
"Simply" is not the same as "Simpler" however.
Simpler is better, it makes software more approachable. It removes the need for phrases like "Simply" and "Just".