That's not clear at all unless you're looking past everything else that's happened leading up to Hamas' rocket attacks.
What started this immediate horror was the intensification of Israel’s ethnic-cleansing campaign against Palestinians in East Jerusalem, forcibly evicting people from their homes to hand them over to Israeli settlers. The incendiary situation was then exacerbated during a Ramadan siege by Israeli forces at one of the holiest sites in Islam, the Al Aqsa mosque in Jerusalem.
https://theintercept.com/2021/05/14/palestine-israel-hamas-netanyahu-biden/
Hamas’s military wing claimed responsibility for the first wave of rocket fire in a statement saying it struck Jerusalem in response to Israel’s “crimes and aggression in the Holy City, and its harassment of our people in Sheikh Jarrah and al-Aqsa mosque”.