I have seen some leftists stand by this statement as entirely true, and I have also seen some leftists dismiss this idea as cope on the part of liberal Zionists who dislike Netanyahu/Likud (and who would like to delegitimize both Likud and Hamas together).
The following are some relevant articles that support this idea:
https://theintercept.com/2018/02/19/hamas-israel-palestine-conflict/
https://www.thenation.com/article/world/why-netanyahu-bolstered-hamas/
What is clear is that Israel has allowed Qatar to fund Hamas on numerous occasions without much interference. However, whether Israel has ever actually funded Hamas specifically with Israeli money is not as well-established (although many of the people who support the general “Israel propped up Hamas” idea definitely imply that this has happened). So as a corollary question, how important of a difference is this?
Palestinian resistance to the Zionist entity is only natural as long as there are Palestinians and Israel maintains its presence as a colonialist ethnostate. The Mossad, Israeli intelligence apparatus or even the American intelligence apparatus is aware of this contradiction. When presented with organized, secular Marxist groups like the PFLP intelligence agencies do what they always do; they infiltrate, split the org, sow dissent and make terrorist groups go after the threatening groups. An interesting detail to note is that the new group is not necessarily fruitless, it’ll just be less threatening to the state than the organized Marxist group that they were targeting. This is not very different to the NOI replacing the Black Panthers.
I have nothing to say about whether Israel funded Hamas directly or indirectly, haven’t looked into that issue.