so who is greater in rank? Khomeni or sistani?
Wrong question. Khomeni died so Sistani is the "highest-ranking" Shia Marji' right now in Iraq, Saudi, Kuwait, Lebanon, Bahrain, and Shiite Pakistanis and Indians. He is not in Iran, but overall, he is the no.1 Shiite Marji' in the world.
BTW, I am in no way saying that he's liberal or nice. On the contrary, he has some seriously fucked-up rulings. For example he is staunchly against mixing between the sexes even in weddings and family gatherings. He forbids chatting with females on the net even for friendship.
And unlike most Muslim scholars, he think it's not permissible for Muslim men to marry Christian or Jewish women. In Shia theology there are 2 types of marriages: permanent (regular) and temporary (aka pleasure marriage). He says you can only marry a Christian or Jewish lady temporarily but not permanently.
So yeah he's very conservative. I'm not defending him. All I'm saying is that Muslims do not consider people of the book unclean. Edit:
just checked, apparently Shiite theologians do consider kafirs who are not people of the book (hindus, sikhs..etc) ritually impure. So the website is not totally wrong.