I mean, look at this (from a bible site) lol
1. Psychic effects. Masturbation has a tendency to isolate its captives psychologically and socially. In masturbation, the person is focused on self-alone even though he or she usually is fantasizing about someone else at the same time.
2. Emotional deprivation. It is impossible for the one who is practicing this habit to experience the full extent of sex emotions. Therefore, in short-circuiting the emotions one can easily be removed from the world of reality.
3. Damaged sensibility. The habit of masturbation has a tendency in numbing the mechanism of the sexual organs if practiced excessively. This lessens the sensibility and thus detracts from normal sexual relations of married life.
4. Self-gratification. The emotional background of self-gratification is not the least bit healthy and usually militates against the home, wife and family because it is focused only on self.
Notice above, it never says "EXCESSIVE" masturbation. Just masturbation.
Science weighs in:
While it once was regarded as a perversion and a sign of a mental problem, masturbation now is regarded as a normal, healthy sexual activity that is pleasant, fulfilling, acceptable, and safe. It is a good way to experience sexual pleasure and can be done throughout life.
In general, the medical community considers masturbation to be a natural and harmless expression of sexuality for both men and women. It does not cause any physical injury or harm to the body, and can be performed in moderation throughout a person's lifetime as a part of normal sexual behavior.