Protecting the imams

[Furkan]

Assalamu alaykum

This might not be a "5-star" topic, but this came up on my mind:

Rasul'ullah (saw) was ordered by Allah to preach the one and only Islam and he (saw) did this without any failure (may allah protect us from such thoughts). And whenever Rasul'ullah (saw) was in danger while doing dawah, Allah protected him in such cases (many examples which we all know). So there wasn't any possibilty for anyone to get misguided/not becoming muslim because of any lack of dawah effort. So the mission was all a succes.

Let's go to the last days of rasul'ullah (saw) and beyond 'till the 12th imam. According to shiites, eveything went wrong here i.e. people corrupted the message, opressed Ali ( sounds crazy right?), Fatima got killed, the rest of the imams were opressed/killed and so on... thus the laymen people weren't able to get any information about this "real" islam which should be kept preached by the imams (who only lived 250 years in total -_-).

Now comes the question:

If all of shiites stories are true, then why didn't Allah protect the message, the imams, ... in such cases from the first day on since Rasull'ulah's (saw) passing away, just like He (swt) protected rasul'ullah and the previous prophets and saliheen (who are lower in rank than the imams, according to shiites btw) to make them succeed in their message?

[Husayn]

Twelverism was spread by Shah Ismail in the 15th century, taking it from a small sect to a large sect.

Allah (swt) apparently saved and spread the true religion through a drunkard who declared himself a god.

[Rationalist]

According to the only the 12th Imam can abolish taqiyyah.

[Ibn Yahya]

Twelverism was spread by Shah Ismail in the 15th century, taking it from a small sect to a large sect.

Allah (swt) apparently saved and spread the true religion through a drunkard who declared himself a god.

Worse than that. The Safavids were psychotic sadists. Hold on I'll quote from an Ottoman eyewitness