No, he's not wrong.

Going back in history a few centuries ago, Zaidism entered Yemen with the coming of that guide to the truth, Yahya bin Hussein, may Allah have mercy on him, who is buried in Saadah, and to whom the al-Hadwai school is attributed.

Guess who called a Zaidi who brought Zaidism to Yemen a guide to truth and then prayed for him?

al Qaeda in the Arabian Peninsula, Sada al Malehin, Issue 12.

So please, tell me that al Qaeda treates Zaidi Shias, who they believe are Muslims, the same as Alawite Shias, who they believe are non-Muslim (as the bulk of Sunni Muslims also do).

You can be a Catholic Christian and be a Jesuit OR a Dominican - but either way you're still Catholic.

Uh no, those are all orders under an established sect, Dominicans/Jesuits/Carthusians/Whatever do not say they are different sects. Here's a key difference between Alawites and Zaidis:

Alawites believe that Ali, Muhammad, and Salman the Persian are all God.

Zaidis believe that even asking one of those for help is a major sin if not outright apostasy because they believe Muhammad is a prophet, Ali is an Imam, and Salman the Persian was just a normal person.

They have completely separate books, completely separate views on God, completely separate source books, completely separate views on just about everything. Practically the only thing they share is that both believe that Ali should have been the first Caliph, and hence they are both called Shias.

The difference between Alawites and Zaidis are larger than those between Catholicism and Mormonism. It would be as if you are calling Catholicism and Mormonism the same sect because they are both fall under Pauline Christianity (as opposed to Ebionite Christianity).