Many pedophiles also decide to be abstinent. That means, they decide for their whole life not to perform the sexual activity they really want. A decision which is very harmful for the pedophile himself.
This is the most trivial and obvious reason. But, if there is a situation with a child which wants to make sex and promises not to tell, the sexual desire is usually greater than the fear.
Usually the fear does not lead to abstinence, more probably it leads to more anonymous, less "dangerous" from this point of view, forms of sex (anonymous singular contacts, prostitution, sex tourism) instead.
The prior result of this decision is that the pedophile does not make sex with children and that's why there will be no of the (real or imaginary) harm which may be connected with pedosexual relations.
But there are also some possible negative outcomes of this decision. IMO, abstinence is a good decision only for people which are strong enough to avoid these effects.
If sexual desires are not fulfilled, it is possible that they become much more powerful and painful. Thoughts about sex with children may become an addiction.
This is very harmful for the pedophile. The stress may lead to sickness (neurosis?). He often wants to get help from therapy. I have no information about the possibility to help with therapy, but reading NMV I have the impression that it is sometimes successful.
The sexual desire is very powerful, and the addiction described in the previous point may become so powerful that the pedophile is loosing the control over his desire. This is usually connected with alcohol and/or drugs:
If the pedophile makes in such a state sex with a child, this contact may be much more harmful for the child than anything he may have done in a "normal" situation. In this state, very nasty and violent crimes are possible.
If an abstinent pedophile has contact with children, they are often able to feel his inner conflict of the desire to have sex with them and his decision not to make sex. He may reject the child which wants more tenderness or even sex. This may be explicit (saying no), but also often implicit (avoiding to touch, avoiding to be alone with the child).
This may be harmful for the child especially because it usually cannot understand the real reasons for the rejection. It feels only that there is something wrong - may be with him, may be with the adult, may be with sex.
Often a pedophile which has decided to be abstinent tries not to have contact with children - to avoid temptation.
Let's compare this behaviour with the behaviour of a pedophile which has contact with children. Even assuming that sexual contacts may be harmful, nobody claims that the (usually much more) non-sexual contacts are harmful. Usually they are positive. We see, that many children loose positive, tender contacts with an adult who loves children.
But I disagree with the point of view that this is the only moral decision, and all other decisions are amoral. Moreover, there are reasonable arguments for considering other decisions as better.