Goodness me! this is a good deal better than the wipe-&-reinstall typical of a hacked ’Doze server — and in fact, that’s what it recommends for a root-level compromise but it has calm, sensible advice for unhacking a box, even those facing a root-level hack and under pressure to not wipe-and-reinstall the box.
And it starts hitch-hikers’ guide style — Don’t Panic! — before listing those many sensible, practical & effective steps you can take.
There’s no magic recipe here for waving some conceptual wand & deftly sanitising a system (BTW, don’t trust anyone who makes it look that simple), but there are good, reliable, steady directions for safely & carefully producing the same effect using more mundane prinsiples.