Yes. Hamas are terrorists who threaten Israeli interests, the defense is justified and I hope they take Gaza and allow Gaza City to be an autonomous state within Israel.
Israels siege, occupation, and collective punishment are all illegal under international law. Hamas resistance to occupation is legal.
Israel is a terrorist state with increasing number of countries recognising that. Hamas although dubbed (by some countries) as a terrorist organisation is far from it. Of course those governments that do not officially recognise Israel as a terrorist state often have vested interests in Israel.
The Israeli government does pay people generously a lot for promoting Zionism and justifying Israel's heinous crimes on Facebook Twitter , forums and other social media.
I would also look up the leaked document Frank Luntz made for Israel which studied the best language Israel government could use to defend their illegal activities.
Basically there's no point trying to argue against Israel's crimes because it's prima facie obvious what Israel is doing is criminal. You would probably be arguing with someone paid to defend Zionism.