She does not refute that. What she says is that you cannot have Button 4 assigned to "IE Forward" and Button 5 assigned to "IE Backward" at the same time - that the software requires you have an Easy-Shift key set to one of them.
You only need an easy-shift button if you want to use that featuire, but of course you can change the buttons to backward/forward?
The valid downside is if you want both, normal back/forward AND easy-shift you would need another button - or a roccat keyboard - however i didnt read that out of that review.