The obvious answer is that xkcd is published under https://creativecommons.org/licenses/by-nc/2.5/
which means that as long as credit is given and no profit is made (nor further second-hand changes made to the licencing that allows subversion of this) the genuine
Randall Munroe Experience™ can be copied and shared freely enough, and not only is this not a copied work, it isn't even a cut'n'paste derived
work, but hand-crafted anew (thus falling well outside the accreditation requirements).
It's not even as if stick figures were Randall's creation (even something as recent as the iconic Xiaoxiao series started four years before Randall) and you can go back centuries (Sherlock Holmes and The Adventure of the Dancing Men is the best example that comes straight to mind to demonstrate this, but you could extend this to paleolithic instances, I'm sure, if you really wanted to) and the constraints of a comic strip practically force other conventions to converge in various ways. And it's clearly attributed to a non-Randall source, with a marginally different-to-Randall style and handwriting as an added bonus.
But, whilst marginally short of proof, I would imagine it is
inspired by Randall's works (as a fan or by mere glance), and the Facebook-depicting comic prior to the one currently linked to shows an increased shared level of common interests and direction of creativity.
were Randall, I think I'd be happy to be inspirational, whilstsoever it is clearly not a full on 'fakcd' attempt aimed at dividing the market share or defaming the 'original'. But then if I were Rndall, I'm not sure exactly what other feelings I might have, and I probably wouldn't be posting here. Plus IANAL.
(But note to the regulars in the "there's this xkcd cartoon that I vaguely recall" thread to perhaps add this webcomic to the list of 'easily mistaken for xkcd' ones, along with all the other ones that look far less
easily mistaken for xkcd, visually, even through the mists of dodgy recollection... Right?