I think the grandparent was speaking more of knowledge then possession of items. Many anti-gun progressives seem to know little to nothing about guns, be proud of their lack of knowledge, and recommend passing ignorant laws that will do nothing to reduce violence. It seems kind of appropriate to compare them - their attitude seems like "Guns are always bad, unless you're the Government, you shouldn't know anything about them or have anything to do with them, and just run away if you see one". Sounds kinda like "Sex is always bad, unless you are married..."

I think they thought they had a clever talking point that exposed hypocrisy or cognitive dissonance but failed to take into account that guns aren't dicks so the analogy falls apart immediately.

Also what about constant denunciation​ of military colonialism, police shootings and the militarization of law enforcement makes you think the anti-gum crowd makes an exception for the government having guns.