So, what @[email protected] said is correct.
The existence of Hamas, and their inexcusable actions, are a direct consequence of Israel's militaristic apartheid and colonial oppression of the Palestinian people.
Hypothetical: If there was record from mid-WW2 of Jewish resistance fighters committing actions against the German population that are of the same nature as what Hamas does to Israel today, would that have made the oppression and violent action of the Nazis valid? Or would that be a distasteful, yet potentially necessary reaction to the conditions that they were subjected to?
I'll address your source in a moment, but I was more aiming for what socio-political conditions might cause a group like Hamas to decide they need to take the action they have taken.
Hamas exists due to the (as of today) 3/4 of a century of oppression that the Palestinians have been subjected to as a result of the creation of Israel after WW2. When the was ended, it was decided that the European Jewish population needed a safe region, so the British and Zionists (reminder that Zionists are often christians and that the creation of Israel was a "biblical prophecy") pushed the Palestinians out of their homes to create Israel, the land for which was forcibly partitioned and claimed as a result of a funded war. Many Palestinians still have the keys for the homes they were forced out of.
This isnt even detailing the 1967 repartitioning, or the long standing and repeated mistreatment of people within the open air prison that is the Gaza strip and the Palestinian permitted areas of the west bank, or many, many other things.
Hamas is the result of decades of oppression and dismissal of the Palestinian people.
Now, regarding your link, yes, this is the 1988 hamas covenant(it was softened a little in 2017) and I dont really care about it in regards to whether or not Israel should be carrying out its actions. I posed this hypothetical to another user but I'll shorten it to restate it here:
Hamas has done terrible, terrible things. During WW2, the Nazi's claimed that the Jewish people had done, or were planning things of a similar nature, in order to justify the "necessity of the holocaust"(not a quote, just wanted to make clear that it wasnt my sentiment). If there were groups of Jewish people who had done things like Hamas has done, would that justify the holocaust? If you answer correctly (correct answer is "no it wouldn't") then why do the actions of Hamas seemingly justify the indiscriminate and unceasing killing of Palestinian civilians?