Easy reading is damn hard writing.
Clear information is information that users can understand the first time. They don't need to reread it to untangle grammatical connections, sort out excess words, decipher ambiguities, figure out relationships, or interpret the meaning. Clarity in technical information is like a clean window through which you can clearly see the subject.
The first time that most writers try to write about something, words don't tumble out clearly. Often, to break through a block, writers write as if they were speaking, but this approach introduces problems such as unnecessary words, ...