Hezbollah are not the Lebanese government.
The military wing of Hamas is not the Palestinian government.

The people of each place may sympathise with the (terrorists/freedom fighters) but they are not the actual fighters or killers.

Even if retribution by Israel against Hezbollah and against the military wing of Hamas were justified (sort of rather like the British Army shooting IRA terrorists don't you think?) how would that justify Israel destroying the infrastructure of the Lebanon and Gaza, and killing the civilian population there?