I'm one of the distressed members of the Muslim Ummah. My family resides in a Muslim country in the gulf. I always had high respect for the Gulf States as far as practice of Islam is concerned. But unfortunately these days when I returned from USA (where I'm studying) I have realized that we Muslims are being humiliated due to our lack in dedication for Islam. We had regular lectures in the local cultural foundation, which were cancelled as the cultural foundation is for cultural activities not Islamic lectures. Subhana Allah! Then where should we expect Islam to be a part of, the west? The morals of the people here are deteriorating. I feel so helpless and my heart aches. Is there no one who can stand up to this oppression? No one? Are we supposed to always keep quiet and bear all this in silence? Is keeping silent to such injustice towards our religion at the hands of the Muslims considered decency? Why don't the scholars take authority of the Muslim nations? Why? Why? Why?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

First of all, thank you for your zeal for Islam and your concern about the conditions of Muslims. In fact, one of the characteristics of the true Muslim is to be concerned with the problems of the Muslims and to advise the Muslims and to strive to bring good to them and block evil from reaching them.
As for giving lectures in the cultural institution, it is one of the works that are rewarded Insha Allah. A sincere word from a burning heart might sow guidance in the hearts of those who listen to it. Then, the one who utters it gets great reward as the Prophet (Sallallahu Alaihi wa Sallam) said: "He who calls (people) to righteousness, there will be reward (assured) for him like the rewards of those who adhere to it, without their rewards being diminished in any respect" . [Reported by Imam Muslim ].
The prophet also said: "By Allah! If a single person embraces Islam at your hands (i.e. through you), that will be better for you than the red camels" . [Reported by Imams al-Bukhari and Muslim ].
The reason forwarded for stopping these lectures is nonsense. If culture does not derive from an Islamic basis and if it does not stick to the Islamic teachings, it is then rejected as it is nothing but deceptions, lies and dissoluteness.
Indeed Allah has Ordered us to read and learn but by His Name. Allah Says (interpretation of meaning): {Read! In the Name of your Lord …} [96: 1].
The Islamic culture has to be founded according to the Teachings of Allah and through what Allah prescribed and with the intention that all this is for the sake of Allah.
But, dear brother, do not become pessimistic as pessimism is from the characteristics of disbelievers. Allah Says (interpretation of meaning): {… Certainly no one despairs of Allah's Mercy, except the people who disbelieve".} [12: 87].
In fact, whenever a door is closed other doors are opened for the call to Allah. The Muslim is well-mannered and discerning. So, he always has a way to spread his ideas and invite people to Islam. We think the Muslim nation is in a good state as long as there are people like yourself who are keen on spreading the right religion and who refuse the spread of Al Fahisha (major sins) and who do not accept to coexist with wrong.
As for your question on why the Muslim scholars do not take authority of the Muslim nations. The scholars are doing their best which is to speak the truth whenever they are allowed to do so. So, you should not put on scholars a burden greater than that they have strength to bear. Know also that the Muslim public is the weapon of scholars.
If this weapon betrays them, then they will be like a person who goes into battle without his weapon. If the Muslim public assume their responsibilities and back up their scholars by following their teachings and endeavoring to apply these teachings in their lives, no doubt the scholars will become the leaders and Muslims would then live in nations that apply Shari'a.
Allah knows best.