Can I possibly sue my professor on a discriminatory basis of religion or this is an academic problem to be solved internally?

It was shocking for me; prior my PhD defense proposal that; my supervisor isn't satisfied of the progress been accomplished unlike the other positive comments received from the rest of the committee members without any specific scientific concerns. Thus, I discussed the matter with the Graduate Program Director who is also one of my committee members. She said; "It is clear to everyone within the department that your supervisor won't let you pass" ! The reason -as per her- due to "my conservative dress code" which he criticized from the first day I arrived to the university from overseas and tried hopelessly to cancel my admission. Lately, I found that he was participating in a blog where he wrote few offensive extreme statements against my religions' figures. Where should I start from ?