There was no "Islamic Jihad" in Palestinian groups before the 90s. Religion wasn't a factor in Palestinian politics or militancy before Hamas, and Hamas only became a big player during the second intifada in the 2000s.
I understand you are from Lebanon and from a sectarian background, but that's maybe partly why you have a biased understanding of the groups, ideologies and foreign players involved. You may want to read some background on the history and the conflict from some other sources maybe starting with [1]. Palestinian militancy played a big role, but their religion did not and they were not trying to ethnically cleanse Lebanon or establish a theocracy.
I understand you are from Lebanon and from a sectarian background, but that's maybe partly why you have a biased understanding of the groups, ideologies and foreign players involved. You may want to read some background on the history and the conflict from some other sources maybe starting with [1]. Palestinian militancy played a big role, but their religion did not and they were not trying to ethnically cleanse Lebanon or establish a theocracy.
[1] https://en.wikipedia.org/wiki/Lebanese_Civil_War