https://en.wikipedia.org/wiki/Car_bomb
Most countries don't actually have their intelligence services routinely carry out assassinations and when they do the point of having the intelligence service do it rather than the military is usually to keep a low profile.
... then maybe, just maybe, you've become as much of a monster as the ones you claim to be fighting.
The ends don't justify the means. The means define what ends you can achieve. If your ends are "living in relative peace and safety" (and for the sake of realism we take that to mean equivalent to a country in Western Europe as neither of those things can be guaranteed nor permanent) and your means involve deliberately killing 10x as many people as your enemies while also killing more women and children and not stopping before the enemy is guaranteed to never pose a threat again, then your ends are only achievable if you completely exterminate not only every single militant sided against you but also all of their friends and family who might be motivated by your actions to take revenge. Or more likely, you'll end up outnumbered, outgunned and at the mercy of those who had to endure unspeakable suffering because of you.
If you look at the situation in Lebanon, you have a religious para military organization pointing thousands of rockets towards israel with the aim of "liberating" the land and turning the entire region into a shia islamic empire - military power is almost certainly part of the equation of how to deal with it (along with diplomatic resolutions with other players)
And I really fail to see how taking out thousands of hezbollah members with virtually minimal civilians casualties is not a good thing - my main concern and criticism is that israel is not pushing aggressively on the diplomatic front as well to take advantage of that outcome.