Obviously, it is really important for any community to have room for a vigorous internal debate on the issues of the day. So if some Jews want to dissent from the consensus of the majority regarding guns, that's their right. But to do so in this way, by calling your opponents "bagel brain Jews" and placing them inside Nazi uniforms, is simply a case of Jews utilizing anti-Semitic tropes. The fact that your organization includes a (non-Jewish) Holocaust denier doesn't help things.
The group also is targeting Black politicians who support gun control, arguing that it is inconsistent with a civil rights paradigm. It has to be said that there is some history of gun control laws being used by racist Southern governments as a tool of control against the Black population, and it is also true that the availability of guns was seen as critical by many civil rights leaders to defend their homes against KKK vigilantes (see, for example, Radio Free Dixie). That being said, the Black community today is perfectly within its rights to conclude that the risks to its community's safety from widespread gun proliferation into the hands of criminals outweighs the benefits of freer gun sales to be used as self-defense. Folks can argue that's the wrong decision, but it ultimately ought to be theirs to make.