This is an extremely ignorant position that trivializes "religion". First of all, as I have written elsewhere, everyone is religious. The question is: how good and true is your religion? To call it merely irrational is to show a total lack of understanding of the subject. And because religions are many, it makes little sense to speak of "religion" categorically in this way because they often have little or nothing in common. You have to address and criticize particular religions for particular reasons.
Furthermore, those who defect from the religious faith on which their society or civilization was built often ride the coat tails of that religious faith without working out the logical consequences of their rejection. That is, it is better to describe the rejector as a heretic or an apostate than someone who has somehow freed himself from the faith in question and all its trappings. Many of these ideologies we're seeing are profound distortions or perversions of some selected element of Christianity or previous heretical position. That's one reason heresy was always regarded as dangerous. It comes from the Greek hairesis meaning "a taking or choosing for oneself, a choice"[0] meaning taking a cafeteria approach toward the dogmas of the faith which exist as a coherent whole. Any distortion or selectivity produces severe downstream consequences like ideology. Secularism and liberalism are examples. They are Christian heresies and cannot be comprehended apart from the Christian context within which they emerged.
Nietzsche, who was an atheist, was smart enough to see this. The "Twilight of the Idols" is all about how silly this secular triumphalism, or even just contentment, is because it fails to see that the consequences of having "killed God" are not yet fully made manifest, but eventually will be made manifest because this state of affairs is unsustainable, and that this will result ultimately in total disorientation and chaos (I disagree with Nietzsche that God was merely an instrumental idea, but he did at least grasp the parochial and myopic nature of so many atheists and secular people; for him, atheism was a terrible thing). Intellectually serious atheists are all in agreement about how terrible atheism is (i.e., not the provincial variety like Dawkins). This state produces a fertile ground for ideology, i.e., irrational half-assed false religions.
[0] https://www.etymonline.com/search?q=heresy