According to their Charter (linked earlier in this thread) their goal is the end of the Zionist state and the creation of a single Palestinian State. The Charter says their fight is not with the Jews, it is with the Zionists. Jewish Palestinians would be full and equal citizens in the Palestinian State, and immigrants could apply for legal resident status.
What is the difference between a Zionist and a Jew who wishes to live in Israel? And remember it is Hamas'opinion that really counts, not yours nor mine.
Hamas would not expend so much blood nor treasure if their goal was just a single Palestinian state where all could live in peace.
You can take that with a very large grain of salt. The ideals expressed in the Charter don't necessarily conform with the opinions of Hamas' leadership, much less the rank-and-file militants.
Since Hamas's leadership would have endorsed that charter before publishing I think we can take it very seriously. No salt required.
Hamas are like Bin Laden - they are deadly seriously about what they say and many find that frightening. In the west we are so used to the feckless nature of our government's, politicians and other institutions etc. that it is unnerving to meet those who mean what they say and say what they mean.