Sex control

"Ideology can arouse in some persons regressive forces and lead them to the use of contraceptives. Ideology can justify the desire for money, resentment, envy, unwillingness to share, the fear of risk, or the desire to keep up with whatever Joneses. Ideology can explain these tendencies as contributions to political stability and productivity. But such reasoned sex control works only with a few, and they are strange and sick; their ideological motivations more frequently lead to irresponsible aggression than to discipline. Birth control is sold to the great majority under false pretenses; for them, it is a blind alley to enrichment and there it does not decrease fertility. The use of ideology to motivate individual behavior then is not only inhuman but it is also a fallacious policy. In such private matters, an appeal to patriotism, public spirit, or religion is usually a good excuse— but rarely a good reason." (Ivan Illich, Celebration of Awareness)

In what sense is the phrase "sex control" used here? And what does the emphasized clause say exactly?