Israel has openly claimed responsibility for martyring dozens of high ranking Iranian soldiers in Syria. And their level of involvement in the martyrdom of Fakhrizadeh is well beyond Iran's potential level of involvement in the actions of Hamas in recent days.The USA openly claimed responsibility for directly carrying out terrorist assassination of an Iranian commander.
In the case of zionist sabotage and terrorism, either proxies were used or the action was covert. Thence, Iran is not compelled to strike directly in order to maintain the balance, she can respond through her own local allies.
The equivalent scenario would be if Azerbaijan launches a surprise invasion of Iran and Israel takes credit for it.