We have seen over the past decade that an advanced western army like the US' have built their military strategy around precision aerial strikes. The point of doing so is two fold
Firstly, it inflicts casualties on the enemy without much risk to their own forces. Secondly, the political cost is low with comparatively few civilian casualties even when targets are located
in between civilian buildings.
This is the kind of war Hamas has prepared for. In their case (being on the receiving end) they have prepared to
deny these advantages to Israel.
They have done so by moving their military infrastructure underground, and right
under densely populated areas.
I suspect Hamas probably
thought that having done so, Israel would politically speaking be compelled to send in the infantry without much support from the air or from tanks and artillery.
The IDF has called that bluff though, telling civilians "we're not going to give up our advantage in fire power, you better get out of the way"
They
are paying a heavy political price for it. In that sense it's a win for Hamas. But they're not getting the urban warfare they hoped for.
And frankly, at the end of the day, it is quite doubtful it makes a difference in the total number of civilian casualties. It does have a big impact on IDF casualties though.
But that's what any nation does in war. You may try to spare the civilian population of enemy territory, but you're not going to risk high casualties or big delays that may affect the ultimate outcome.
Ok having said all that, I do highly doubt that this war is worth it from an Israeli perspective. My only argument in their favour is that 1) they had sufficient grounds to do it. In a similar situation, any country would reserve the right to respond with a military campaign and 2) the way they go about it is sensible from a strategic pov. It does not have to be an expression of excessive or intentional brutality, if you consider the alternatives.
If my writing is confusing, try this.
Gaza’s Underground: Hamas’s Entire Politico-Military Strategy Rests on Its Tunnels