Because people like Trump and Rob Battisti have clearly said, if Country 1 has nukes and invades Country 2 with no nukes, then the way to avoid nuclear war is to give Country 1 every thing they want.
You are arguing every day why not doing that and supporting Ukraine 'risks nuclear war or WW3' as the reason to capitulate to Putin and you WOULD NOT if Ukraine had nukes.
The reason we now need a shift to every nation arming up is because Trump and people, like you Rob, have switched to a view that 'the US should not only not try to ensure those with out nukes are not over run by those with nukes... but the US should help facilitate them being run over as a way to avoid nuclear war or WW3.'.
How can anyone argue that it is the view that Trump (and you support) that necessitates every nation, who can, now getting nukes?