If the US had terrorists at their border who had recently staged an attack that killed scores of people in the US and the US sent exploding pagers, radios etc., people in the US would be cheering.
Israel is at war with terror groups that want to destroy it if they could. I don't see a problem with what they did. Screw around with Israel and you better watch out. I think it is a pretty sound message to send to people who want you to cease to exist.
I guess Israel is not allowed to strike back at its enemies.