What's the issue? The NSN officially disbanded, yet almost all the same members created a 'new' organisation (i.e. they reformed), continue to run events through their front group (March for Australia) and continue to show up to various events together as a group. It is clearly a continuation of the same violent organisation in an attempt to circumvent the ban, something Sewer even talked about at the time of their disbandment, referencing what National Action members in the UK did, many getting arrested afterwards for trying the same thing.

Is this a preemptive ban on any groups that could be anti Israel - before they exist?

Very clearly no. Now, if you're concerned that these anti-hate laws could be abused to censor groups critical of the Zionist Regime, then that's a valid concern, especially if Libs or ON take government in the future. But no, neo-Nazis are a distinct ideological phenomenon, even distinct from Nazism these days.