I am not a fan of that phrase.
The tone and meaning are clearly intended to call a bluff in the political arena. I'm sure in poker and other contests, the best possible counter to a bluff is to know how to call it. But there is a significant problem with this gambit in the context of the debate over the Second Amendment: the other side is no longer bluffing. I'll suggest that they never were bluffing—they just had to keep quiet about their full intent and patiently nudge the needle of public opinion until their radical proposals could gain traction in the mainstream.
Bad news: it worked.
If you don't think there is widespread public support for the complete demolition of the Second Amendment, you need to consider why so many politicians are now openly and unabashedly—proudly, even—running on platforms supporting gun confiscations, bans, etc., and working to implement such policies during their terms in office. Of course, that implies that they are getting elected, too, which used to be much more difficult for anti-gun candidates of any political leaning. Not so any more, in many parts of the US.
So if the bluff has expired, or never existed, that phrase now serves a function that is quite different from what many pro-gun folks think.
Frankly, it's like standing in your open front door in the dark of night and yelling at a prowler: "Hey, come get my family and valuables, you maniac!" All wrong.
Whether on the front steps of your home or your statehouse, you can expect nothing good to come of sarcastically summoning an opponent into armed conflict.
It is also worth noting that the phrase offers no intellectual support for the right to keep and bear arms. None.
All this phrase does is assure the other side, who fear that we gun folks all think of ourselves as John Wayne, that we gun folks all think of ourselves as John Wayne.
Of the ego, by the ego, for the ego.
Time for a new battle cry.