I've been thinking about the same kinds of arguments today, too.
Another line of reasoning I'm too tired to fully lay out right now but that I've seen elsewhere and I think is compelling:
Israel's history of targeted assassinations and arbitrary imprisonment of activists in the occupied Palestinian territories, taken together with the fact of the Oct 7 attack itself, proves that the state of Israel doesn't know who or where the Hamas leaders they supposedly want to target are. So the only 'targeting' they can do is indiscriminate, and the only end point of their bombing campaign is total destruction. And this is borne out in the rhetoric of many officials and much of the Israeli public, and of course in the atrocious, ongoing violence the IDF is right now carrying out.
The impossible goal becomes an excuse for 'no red lines' because no matter how far they go, they can always say they are still not done. This dovetails as well with the analogizing of Oct 7 as an 'Israeli 9/11', the 'War on Terror', and the USA's forever wars in the Middle East.
But your point about the reflexive brutality, the observation that somehow a military response is the only one considered or undertaken here, is also extremely vital. Because part of the rationalization here is absolutely this idea that 'there was no choice', given the desire to uproot Hamas. But of course that's bullshit.