- Secularism purports to be a neutral ground for all religions
If the claim is that secularism in its nature purports this, then it’s empirically wrong. In Revolutionary France, for example, and versions of this carry on there to this day, secularism is the explicit privileging of a universalist liberal humanist (etc.) worldview over that of (originally) the Catholic Church, so that the measure of whether the state is secular is not whether it is “neutral” on all religions, but whether the state permits the Church a role in public life at all. The secular state may permit religious belief and association on the part of its citizens, but this is grounded in the state’s privileged philosophical view of what the rights of those citizens are, so the question of neutrality is orthogonal to the constitution of the secular French state: the state’s secularity will not be measured by whether it is philosophically neutral but whether it is practically/legally neutral to the conduct of its citizens by its own philosophical lights.
Mustafa Kemal Ataturk reconstituted Turkey, after the First World War and the collapse of the Ottoman Empire, on a new explicitly European and Republican and secular model of what a state could be. Outwardly he was a practicing Sunni Muslim, and spoke in terms which privileged Islam as a/the true religion and the religion of the Turkish people and of Turkey, but he also disestablished Islam in Turkey, somewhat after the manner of the disestablishment of Catholic Christianity in France, and forbade religion and religious practice from Turkish public life. In the Ottoman Empire, Islam had been central to the self-conception of the state, and, as with Revolutionary France, Ataturk was concerned with eliminating the social and political power of the imams insofar as it clashed with the philosophical principles of the new secular Republic, granted that in the case of Turkey Ataturk’s goals were arguably more pragmatically oriented towards development than towards a unifying philosophical ideal (although I don’t want to make a sweeping claim by that).
Once again, in Turkey’s case, the question of whether the secularist is neutral seems orthogonal to the issue, since Ataturk doesn’t just say “well we’re going to be neutral now”, he says “religion has held this society back”. I don’t have to endorse Ataturk or the Jacobins or whoever to say that their attitude to religion is non-hypocritical and non-vacuous, and in fact if I do endorse some of their foundational arguments for modern secularism, I can also claim that those arguments are non-hypocritical and non-vacuous components of a modern argument for the secular state. What is sometimes called “muscular liberalism” today has built in to it the argument that its values are, in fact, just better than those which establish religion at the heart of public life.
These are two points of view from the history of the world in languages other than English, but the YouTuber appears to be from America, and speaks English, so perhaps the version of secularism that is being promulgated here is the peculiarly American vision of pop-secularism which, granted, frequently does not have some of the same political features as Revolutionary France or Republican Turkey. This renders his teleogical vision of Early Modern philosophers who each embraced highly distinctive secularisms ascending to that modern American liberal secularism incoherent, but I don’t think coherence is the point here. The YouTuber traduces secularism on the grounds that it claims to be non-ideological, but the arguments there made are not that secularism is non-ideological, so while the argument might be an effective tu quoque at YouTube secularists who claim that non-ideological science vitiates religious belief, that argument is massively overpowered and badly misrepresents the history of secular thought in order to take on its internet rivals.