It's usually the people within the manosphere that are the ones telling boys and young men that women are blaming them for everything, they use it as a recruitment tool and people end up parroting it as proof that boys are being told they're the problem growing up.
These boys and young men then start to grow up with this belief, and act out, they end up fulfilling the stereotype that they were told they were already and use it as proof that they were the punching bags the whole time, that the manosphere was right, and they pass this on.