Sure, those work too. But so do:
we don't need a reason
it's the same as other rifles gun control nuts don't want to ban
not that many people are murdered by rifles
even fewer are murdered by "assault weapons"
even fewer are murdered with an AR15
even fewer are murdered with a legal AR15
the last AWB was stupid and pointless (other than hurting the gun control nut side in the long run) why bring it back?
etc, etc
There are a LOT of good reasons to "defend" the AR15.
and yet all we're hearing is "DEFEND MUH FREEDOMS AGAINST GUBMINT TYRANNY!" Because honestly that argument is so inane and stupid and basically only believed by Alex Jones-type loonies it makes me want to dismiss the entire side on those grounds alone (and come on dude, you work for the federal government, I'd figure YOU of all people would also find it absurd and insane.)
And the article (printed in an obviously not pro-gun website of course) doesn't entirely exonerate everything about an AR-15, for example the author notes that it's popular for being very customizable. But hunting is typically done in a manner similar to sniping and at a distance, and hunting rifles don't have a fast fire or reload rate. Now with such a gun you could do some damage in a crowded area yes, but not as much as one specifically designed for close quarters shooting. So at the very least if the AR-15 can be easily customized to be used in close quarters and for ease of reloading, then there are some accessories for it that serve no valid purpose and should not be sold.