It isn’t compatible with basic principles of liberal government to offer “What’s the harm?” as the basis for a restriction or policy. There needs to be a clear and just basis for government action, and a commitment to repealing or abolishing policies that do not prove to be worthwhile.
The same thing goes for asking “Why do you need that?” and if people don’t have a reason you like, taking that as a basis for restriction. In a free society, the people don’t need a reason — we can do what we like. It’s the government that needs a reason. We should be questioning proposed policies, with an eye to the public benefit, not because of any love of guns, but merely out of a basic requirement for government accountability.
30 rounds is standard? That's terrifying.
Anecdata but the NZ shooter had large clips (many dual large clips taped together in fact), and Las Vegas shooter had some crazy "niche" shit.
If it's so niche that nobody cares then what's the harm in restricting things like that? People don't need 40 round magazines to shoot targets.
They don't even need semi-auto to shoot targets, but that's crazy talk.