But that is true for any sect, it also happens in Sunni sect also, but you can not blame all of Sunnis for that. Anyways I am not here to defend them but what I mean that we should be careful saying such things on these forums.
First of all there is no such thing as sects in Islam. Thats a topic for a another discussion. There are some who do this on the other side. But this is the popular belief system of the shia. Some naive shia themselves might not realize they have turned their imams into 12 super prophets but this is what their belief system revolves around among other khurafa like imamat and vilayat.
The only difference between them and mirzais is that mirzais made the mistake of calling mirza a Prophet. If they would have called Mirza just an imam, it would be another recognized sect in Islam just like deobandi or brelvi. In fact and I know this is going to be very controversial statment, if you replace the word prophet with imam in mirzaism it is a much more saner and closer to the standard sunni Islam.
And just replace the word Imam with prophet in shia-ism* it is an extremely blasphemous and insulting to Islam, all the prophets, their progeny and companions as you can get.
*Which the shia only say out loud because they know if they cross that boundary there is no coming back from it and they will totally be ostracized by everyone, but for intent and purposes Imams are like I said Super Prophets for the shia.
So my objection is simply clerical and on technical grounds. If Mirzais are officially declared non muslims with one prophet, then so should the shias be will 12. Or declare Mirzais also as Muslims.
Because in both scenarios one sect is being treated with prejudice while the other is scott free. Laws should be equal for everyone. Either declare them both non muslims or both Muslim sects. I'm good with either way, but you can't have it both ways.
