This really is settled stuff. I don't think ANYTHING I could provide you would satisfy you. And, I don't intend to do anything of the sort, as to truly know truth is only possible with personal research and vetting, and NOT spoon fed as seems to be animating your approach.
However, FBO others, here is just 3 seconds of search time, from the perhaps thousands of sources, that even the leftist google search provides:
GOLDSTEIN: Israel’s enormous blunder — it helped to create Hamas
You’re good at providing links, but you’re not very good at reading them.
While Israel did have backdoor contacts with Ahmed Yassin, a blind wheel-chair bound Muslim who had founded an organization in 1973 called Mujama al-Islamiya, this was before the formation of Hamas. At the time, Mujama al-Islamiya was focused, or claimed to be, on social and religious causes rather than militancy. It was viewed as a counter-weight to the influence of the secular but more militant Fatah and PLO.
Over the following decade, the organization became more militant, eventually leading to the founding of Hamas in 1987. By then, the Israelis had long since stopped any support it may have given to the earlier organization.
Were the earlier contacts the Israelis had with Yassan, a mis-calculation? Probably. But we’re talking about events that happened 40-50 years ago prior to Hamas’s founding. The growth of Hamas into what it has become today, took place well after the Israeli’s had cut ties with Yassan.
Here’s some more background on the founding of Hamas:
https://en.wikipedia.org/wiki/History_of_Hamas