They, along with Syria, are (allegedly) a major source of funding and weapons for Hezballah
According to Noam Chomsky Israel was also a supporter of a similar group called Hamas in its early days. This was to combat fatah. What's going on here is the polity don't really care about who they support as long as it furthers their aims.
Our polity views conflict as an opportunity to be exploited. An example would be Turkey, in 1996 there was an assault on Kurdish communities in the south. 30000 villages were bombed and there were 1 million refugees. The American government responded by making Turkey the number one country to receive US aid, war is profitable. This is not an isolated incident if your an ally them your crimes are hidden. Saudi Arabia is like Iran a middle eastern theocratic state with human rights issues and [even greater] involvement in international affairs (particularly in the Muslim world). Why are Iran sanctioned and not Saudi, is it just oil. Look at Syria and Jordan both are next to each other (Arabs call this region the Sham because of cultural similarities between their Arabs who live there) both are secular states, both are oppressive regimes, one is on the terror list the other is ignored by the media and given aid.