The reason that government writing (and institutional writing in general) is often so bad isn’t because the people writing it don’t know how to write plainly, but because they don’t want to.

When you’re reading something from an institution that seems unnecessarily obscure or indirect or passive, there is usually a reason, and that reason is usually that if they had stated the plain truth, it would make them look bad.

There was a great geeky essay about the language of the video game portal that went into this:

https://www.gamasutra.com/view/news/114904/Analysis_Portal_a...

And of course the classic Orwell essay:

http://www.orwell.ru/library/essays/politics/english/e_polit...