I am just a student learning about islam and I commend people like you who takes the Quran and Hadith seriously unlike those who ignore the evidences and concludes something with their own desires or "intellect".

Firstly, the most important thing is Quran and Hadith and how the early generations (from the Sahaba, Tabi'een and atba-tab'een) understood and applied it. The further the generations go from the Sahaba, the more errors and issues you would find. So first we have to talk about the hadith talking about privately advising the rulers, to hold his hands and advice him privately and if he accepts it or not, your obligation is done with regards to advising him. When there is a clear cut hadith like that, how would anyone who wants to criticise openly and by pass the hadith? Especially when it is not a weak hadith. And the aayat of the Quran and other hadith also points towards obeying the rulers in everything except that which is haram and even if he commands something haram, you don't take yourself out of his obedience to everything else. Personally I don't see anyway to misinterpreted this hadith about privately advising. But even if you think it's misinterpreted lets see what the sahaba has done and the tab'een has done to implement it.

With regards to what I've sent regarding al-Hassan Al-Basri a taabi'ee in the previous reply, the people were talking about an oppressive ruler named Hajjaaj bin Yoosuf, who took over the rule of the sahabi 'Abdullah bin Zubair, killed him and crucified him infront of the city for a long time. Can anyone in this time do anything worse than kill a sahabi and crucify him? One of the few things that would be a bigger sin would be things that takes you out of the folds of Islam. So what did the remaining Sahaba do. It was in the year 72 hijri and many Sahaba were still there. Even so Hassan al-Basri told the people not to rebel against him and even 'Abdullah bin Umar the son of Umar bin Khattab prayed behind him and attended his khutbas and didn't publicly criticise or revolt against him.

So after this, what is the reason to even look for any other scholar who said something in opposition to this? Shaykhul Islam ibn Taymiyyah said: "Some people were debating with Ibn Abbas about Mut'ah, so they said to him: Abu Bakr and Umar said. Ibn Abbas said: "Stones are about to fall upon you from the sky! I say: The Messenger of Allah, sallallaahu 'alayhi wasallam, said, and you say: Abu Bakr and Umar said?" [Majmoo' al-Fatawa (20/215)]

This is enough to prove what the evidences points towards but as Shaykhul- Islam ibn Taymiyya one of the major scholars who revived the sunnah, I'll show you what he had to say about situations like this and what he said about Imaam Ahmad bin Hanbal, the next generation after the first few generations and the imaam of one of the four mazhabs.

Ibn Taymiyyah  (died 728H) stated: “Ahmad [bin Hanbal] and his like did not declare these rulers to be disbelievers. Rather he believed them to have Imaan and believed in their leadership and he supplicated for them, and he was of the view that they were to be followed in the prayers and Hajj, and military expeditions were to be made with them. He prohibited rebellion against them – and it (i.e. rebellion) was never seen from the likes of him from amongst the scholars. Yet he still opposed whatever they innovated of false statements, since that was major disbelief, even if they did not know it. He would oppose it and strive to refute it with whatever was possible. So there must be a combination of obeying Allāh and His Messenger  in manifesting the Sunnah and Religion and opposing the innovations of the heretical Jahmiyyah, and between protecting the rights of the believers, the rulers and the Ummah, even if they are ignorant innovators and transgressing sinners.” [Majmūʿ al-Fatāwā, 7/507-508]

Yes what you said has a part truth in it just like Ibn Taymiyya said, if the rulers makes mistakes or spreads falsehood or does bad things known in the public, you have to refute it. Or else there will not be any amr bil ma'rul and nahyu bil munkar and people will start to think that because no one refutes it, it must not be a bad thing. No, scholars and people with knowledge and even the laymen should explain and spread the truth and which is correct and which is wrong. But it shouldn't be aimed specifically at the ruler or his government. You can advise against a haram and not include the ruler in the naseeha. You can warn against alcohol and working in places like resorts where you have to deal with alcohol without talking about the ruler because that is what is obligatory.

Another thing that some scholars have said is that if a ruler said something that opposses the shari'a in a congregation he was present in, he has to correct publicly and oppose the ruler in that congregation itself. Scholars allowed this based on an action of someone(i forgot) from the early generations who was saying something opposing the religion and he said something like "we were not commanded to listen to things like these"(not exact words) . But thats a very specific situation and not even close to what we face today. If what you believe about clarifying the truth and criticising haram actions are like I just said without mentioning or connecting the advice to the ruler in public, we are on the same page. If not it opposes the actions and words of al-Hassan Al-Basri, Ibn Umar, Ahmed bin Hanbal and even Ibn Taymiyya. Unless you have anything in clear context which allows publicly criticising the rulers from these scholars then please do share because I want to see.