Great minds think alike.
If indeed legislation is passed banning private, undocumented transfer of firearms, and all become ‘registered’, and ‘they’ come for them, do we really think ‘they’ will just take those in the register? Or will they use metal detectors to look for ‘illegal’ guns secreted in the walls or buried in the yard? Or detain individuals until they give up their stash? (See the War on Drugs and Prohibition for historical context.)
Yeah, that alone is very good reason not to register anything.