Let's do a thought-journey, what physicists call a gedanken experiment. Let's pretend you are a 18-year old male, whose parents have donated him to a Hindu or Buddhist monastery. The oldest son inherited the farm, and there is nowhere for you to live. So there you are. And there is no escape at all, ever. You are part of the Feudal system. If you leave the monastery, you will simply discredit yourself and your parents and will forever be known as a renegade or fallen monk. So really, there is no escape. There you are, a healthy 20-year old male, whose testicles produce five hundred million sperm each and every day, and who gets an erection at the slightest thought of sex, gets aroused just from the brushing of the cloth of the robe against his penis. Around you in the monastery is a range of males, aged 16 to 60, half of whom are sizing you up as a sexual partner or slave.
Your situation as a monk is probably that you are not there by choice. It is as if you have been drafted into the army. And even if you are there by choice, what is the choice? What would be going on in the mind of an 18-year old if he says, "I forever renounce sex. I renounce ever finding a mate. I renounce all personal relationship, forever. I swear to be in poverty for the rest of my life. I swear to completely and unquestioningly obey every monk who is senior to me, for the rest of my life, no matter what they say. I swear total and unquestioning obedience to my lineage." You may have just wanted to get out of town, get out of the house, and to do that, you entered a monastery.
So there you are, and guess what? All your life energies, that could go to doing work, starting a family, developing a craft, having friends, building a life for yourself, all these energies have to be redirected. You actually have to kill them off. Any impulse you might have, when given an insane order to comply with, to say, "Shove it," has to be broken utterly. And any desire you have for women has to be killed out, entirely. Say you are driven wild by lust and seduce a village girl, either taking her virginity or making her pregnant. She will be ruined – there is no possibilty of marrying her. She may commit suicide, her family will be totally dishonored, and her father and brothers will come and burn down the monastery, even though it has been there for hundreds of years. So you have to, at all costs, kill your sexual desire.
Meditation in such circumstances is part of a war on the self. The need is almost medical, in which amputation is called for. You need to amputate your desires, ambition, individuality.
The next most common hazard is that you do meditate for awhile, and what you do inside is conduct a war on yourself. Meditation books are full of negative judgments that monks and nuns have against householders: "You are doo materialistic, you move too fast, you think too many thoughts, you have passions, you are independent, you are rebellious, you are sexual, you have an identity, you love yourself and love your life."
Traditional meditation teachings have elements in them that are mildly harmful, by design – it is necessary to break the spirit of nuns and monks and make them submissive, kill their wildness.
If you want some examples, you might read A Tale of Two Paths.
Monks and nuns are called renunciates, because they take vows of poverty, celibacy and obedience: I renounce the desire to own anything, I renounce sex, I renounce my ego and independence and vow to obey whoever my superior is. These vows can be very liberating to someone whose destiny it is to be a monk or nun. The individual can even glow with an inner luminosity. But they also become radioactive in a way, and if you study with them you may get radiation poisoning, as if you got too many x-rays.
Monks and nuns tend to see everyday life as a disease. They suggest you internalize toxic attitudes toward yourself as medicine. Slow down, kill out your passion, become submissive, cultivate disgust instead of attraction, and dissolve your identity. These are medicinal attitudes that monks and nuns cultivate in themselves. However, if you are not a monk, these attitudes are simply toxic, like taking antibiotics if you do not have an infection, or drinking radioactive iodine to kill your thyroid gland. If you do not have a disease, they just weaken you. This weakening takes three forms, which are all by design: