A fair take by the newsmedia would have been to use the word “retaliatory” for Hezbollah’s attack just like they used “preemptive” for Israel’s.
Both attacks have causes, so if one is mentioning the causes for one set of attacks (which makes it seem less senseless) one should also mention the causes for the other set of attacks.
The manipulativeness here is not the use of “pre-emptive” for Israel’s attacks, it’s in the systematic framing of Israel’s attacks as having “a reason” (in this case pre-emption) whilst the other side’s attacks are portrayed without mentioning the reason and hence sound senseless to anybody less well informed.
What they’re doing here is called “spin” or “framing” and it’s a Propaganda technique meant to project a more favorable impression about one of the parties involved.