I mean... if you have a reasonable conspiracy theory; out with it. Who is being forced into debt? Who are the beneficiaries?
The idea that western powers are the puppet-masters of Hamas seems extremely unlikely. Indirectly funded by the west? I'm kinda open to that- but that doesn't make Hamas "not-real", or a puppet. They have clearly been a Palestinian party of the PA for decades; and have the destruction of Israel as one of their interests.
To answer the question asked in the OP... Hamas is pretty much, objectively responsible.
The "poor innocent Palestinian civilians" approach isn't going to work; because people understand the difference between Hamas directly targeting random civilians, and Israel targeting Hamas with civilians dying as collateral damage. Jesus told his people when they saw their city surrounded by armies, it was time to leave. He didn't tell them "stay in Jerusalem and and be a meat-shield for the Zealots; and then demand sympathy from the whole world when the Roman's kill you".