My cynical side wonders why Iran would ever sign an agreement that blocks Iran from doing something that benefits it. My cynical side also knows Iran very well.
Not that we could take Iran at its word, but shouldn’t they agree to sign the convention prior to concluding a deal with Iran about their nuclear program?
Lebanon hasn’t signed it either. Other non-signatory countries with Islamist political movements include The Gambia and Chad. But they don’t have nuclear programs.