You mean other than the extremist view of religion and implementation of religion running their legal system, their authoritarian control of Gaza, and their belief in racial superiority?Why do you think they are right wing?
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Back in the 60's and 70's Hamas' progenitors were engaged in charitable works which isn't exclusive to the left. Since they go t a taste of power in the 2nd intifada, they decided that terrorism and violence would somehow achieve their goal of eliminating Israel.
Even their recent policy document makes it clear that they religion as the basis for their control.