I don't think anybody accepts school shootings, and anybody accusing half of the population of "accepting" this obvious problem is likely making a bad faith argument attempting to paint their political opposition in a bad light.
I'm sure most of the population wants it to end, but also most of the population isn't doing anything about it, that's why I say most of them are complacent.
The group of people least likely to think guns are too easy to obtain are firearm owners, but even so 38% of them think it's too easy. 34% of Republican/Republican leaning people think it's too easy.
What we can say is most people think it's too easy to obtain firearms. And yet - the issue persists. I'm not trying to make it a partisan issue, I'm suggesting it's (as I wrote) an emergent property of our political system. Majorities can't get laws changed for various reasons.
Source:
https://www.pewresearch.org/short-reads/2024/07/24/key-facts...