The thing is, do they REALLY expect gun owners to support a registry now that you have a democratic candidate openly saying "we are going to take your AR-15"?

You just confirmed the fears. You confirmed the distrust. Now you lost the narrative. You can't say,"no one is coming for your guns!!!" anymore. Because you just confirmed to people that you are. Now you gotta stick to your (lol) guns and convince people on fence why they're worth taking and if taking them is possible without violence. You lost the plot and likely the argument for by doing this, Beto.
And let's be honest. Any progressive or socialist that supports such policy is 100% a fraud.