I didn’t say you cannot copy/paste.
I said: you can NOT copy/paste from M$ Word directly into the Visual editor.
Actually, even for that there are 2 [two] buttons in the Write panel: they look like a small yellow folder with W and T on them. Users just need to get familiar with the tool they are using (instead of writing long useless complaining posts here, you could have spent the time clicking on every button in your admin panel, to learn them…)
W = pasting from Word and will keep some of the formatting
T = will transform the text into plain text (the preferred solution).
Alternatively, you can copy first your Word stuff into Notepad and from there into WP. Clean and fast.