It is not a condition that warnings and refutations come from scholars

Imām Rabee b. Hādī al-Madkhalī stated:
I would be nice that a refutation would be from an 'Ālim firmly grounded in knowledge with the descriptions that you mentioned, but it is not an obligation on every refuter to fulfill these discriptions, and it is not obligatory to complete these discriptions in every refutation, and if we was to make this a condition for every refuter and every refutation corruption would spread and would over come most of the Ummah except for some exceptions of the people.
And what emphasizes the inaccuracy of the refuter having to fulfill these conditions is that you will not find in most Muslim lands firmly grounded Salafi Ulama, but you will find in those lands students of knowledge, and with that Allāh aided them in the spread of Tawheed and refuting polythiesms and innovations and superstitions.
And i ask Doctor Ibraheem if there was a country or countries in which innovations and evil was being spread, and there was not found in that country a firmly grounded 'Ālim or firmly grounded 'Ulama that meet these conditions ,but there was present students of knowledge that had read (Usool Athalāthah) or (kashfus shubuhat),and (kitāb At-Tawheed) by Imām Muhammad Ibn Abdul-Wahāb and the book (Al-Wasatiyyah) and (al-Hamawiyyah) by Shaykh ul-Islām Ibn Taymiyyah and (Umdatul Ahkām) by by Imām Abdul Ghani al-Muqdasi or (Bulugh Al-Maram) by Al-Hāfith Ibn Hajr, and innovations where spread like the innovation of denying Allāh's Attributes and the innovation of the Qadariyyah and the innovation of al'irja and the innovation of commiting Shirk with the people of the graves and other innovations, and there was an abundance of drinking intoxicants, and shameless women, is it obligatory upon them to correct these evils in accordance to the level of their knowledge or is it obligatory upon them to be silent because they are not firmly grounded Ulama…etc?
I believe that Doctor Ibraheem will answer that it is obligatory upon those students of knowledge to correct these evils within the limits of their knowledge and ability and that is in compliance with Allāh's statement: (Let there arise from amongst you a group of people inviting to all that is good (Islam), enjoining Al-Ma'ruf (i.e. Islamic Monotheism and all that Islam orders one to do) and forbidding Al-Munkar (polytheism and disbelief and all that Islam has forbidden). And it is they who are the successful.)¹and in complience with the command of the Messenger of Allāh ﷺ:(whoever amongst you sees an evil then let him change it with his hand. If he is not able, then let him change it with his tongue. If he is not able, then let him hate it in his heart and that is the weakest of Eemān.)²
So who so ever amongst them has the authority then he should change the evil with his hand or change it with his tongue, and the person who does not have the authority then he should change it with his tongue, his pen and his writings, and i don't think any 'Ālim or student of knowledge disagrees with this.
And i think that those students of knowledge that i described that they are silent in correcting evils fall into the statement of Allāh :(Those among the Children of Israel who disbelieved were cursed by the tongue of Dawūd and 'esa the son of Maryam . That was because they disobeyed (Allah and the Messengers) and were ever transgressing beyond bounds.
They did not used to forbid one another from the Munkar (wrong, evil-doing, sins, polytheism, disbelief, etc.) which they committed. Vile indeed was what they used to do.]³

From the book: A clarification of the mistakes and transgression in Ibraheem ar-Ruhayli's advice pg.49]

(1)Surah ((Āl-Imrān)),Ayah[104]
(2)collected by Muslim Hadeeth [49],and Ahmed(3/49).
(3)Surah ((Al-Mâ'idah)),Ayah[78-79]