I think a large part of the cynicism comes from how long the rifle has been in production and how little results we've actually seen.
The ARX has existed in one form or another since 2007, possibly even earlier if you count their prototype carbines, and yet their only users are the Italian Army, Albania, and Turkmenistan.
Civilian production seems to have taken a backseat while various kinks in the system are worked out and more military contracts are pursued.
Comparative rifles from other manufacturers like the SCAR, ACR, or Cz805 are newer systems but are already wider established than the ARX.
The ARX could still prove to be a great platform, and I think if civilian production really happened they would certainly find a niche market both in Canada and the US for a semi-auto rifle, but it just doesn't seem to have been a priority for the parent company.
Alternate theory: It looks funny. Not ###y like a magpul gun.