The clearest example is the mid nineteen 'hippie' counter-culture, which was supposed to be about a kind of spiritual revolution, including many Eastern religious elements, a critique of materialism, the desire for meaning and an escape from alienation, the formation of a more organic and ethical society and so on... but which very rapidly became primarily about the sexual revolution and the other stuff just a camouflage... a tool for seduction, as it were.
But this scenario has been played in many times and places over the past couple of hundred years - a socio-political movement starts out as spiritual, but ends up as sexual. (Indeed, nowadays, almost everything ends-up as being 'about' sex and the sexual revolution.)
Sexual takeover does seem to be a highly significant problem - presumably because it s not just a powerful instinct for humans, but something which spontaneously disguises itself, excuses itself, and operates at many levels.
In fact, sex is nearly all 'in the head' - a sexualized atmosphere may dominate in a person, a group even an institution with only a tiny proportion of actual sex, or none at all: it is nearly-all about anticipation, fantasy and memory. And sexuality is also far more strategic than is commonly acknowledged - with seducers engaging in detailed long-term planning and attempted manipulation.
(The secret that sexuality as a goal of life simply does not work, that sex does not ever or even remotely yield what it 'promises', makes the whole thing a bad joke; and humanity a bunch of existentially pitiful fools.)
Altogether, sexuality is a formidable foe - not to be underestimated! And real religions do not underestimate it; but always have in place some kind of explicit goals and rules.
Both goals and rules are needed; although rules get most of the attention. It is as if, when goals are lacking, then sexuality is the next-most-powerful thing, and will expand to take the place of goals.
So celibacy is one goals which many religions have put into place as a way of controlling sexuality - indeed for many religions celibacy is the highest goal, and the religions regard sex as a failure. This would seem extraordinary and paradoxical, except that sexuality is so powerful that even when it is all-but prohibited and at least strongly discouraged, enough still goes-on to perpetuate the group. However, there are obvious problems with holding celibacy as the ideal.
But marriage (in various forms) with an orientation to family is the main way in which the usurping tendency of sexuality is controlled, and indeed beaten, by religion.
Given this fact, it is surprising to me that marriage has so seldom been recognized as the highest spiritual aspiration - higher than celibacy. But when this happens, the advantages seem obvious.
Marriage with family is the goal, and there are also the rules. Religious people are used-to insisting on rules about sex, but without a goal then rules are merely negative: and a life based around a series of 'thou shalt not" statements is grossly incomplete, inorganic, maimed... and this fact has been noticed, exposed and exploited to the hilt by those who oppose religion.
Among the modern middle classes it is usual to put forward 'a career' as the proper goal of life; but we know from experience that this cannot work - the goal of a career is a pitifully feeble thing to pit against human sexuality! For the obvious reason that a career is a grossly inadequate and impoverished life goal - it simply cannot and does not do the job.
We need to have marriage as the goal, for individuals, and sustained by culture. From this perspective; I find it highly significant that in the modern West it is at best regarded as offensive to propose marriage with family as the proper and best goal of life - this is increasingly taboo; and indeed (in the UK, at least) it is illegal in some situations.
But the spiritual goal of marriage and family is what is needed; it is what is absolutely necessary for any effective and resilient spirituality in modern conditions: and nothing less will suffice.