There are individual differences: some abusers certainly do experience reactions of shame and remorse, and others do not because they get addicted to the pleasurable feelings produced by inappropriate sexual behaviour.
Carrying a secret involving guilt can be a very heavy burden, and many sexual offenders against children have a well-developed moral sense. However, as with most kinds of negative behaviours, at the time of acting-out there is often an over-riding of the conscience by the person’s strong feelings, urges and impulses stemming from unmet needs that were created by their early experiences, and which remain part of their personality.
Feelings, urges and impulses that resurface in adulthood relate to unmet or thwarted emotional needs in childhood that are recorded in memory as emotional pain, and as negative beliefs about oneself or the world. The worst and more chronic offenders believe that the world is bad, rather than their own actions. However, some people, including some child sex offenders, carry a biased and irrational tendency towards self-blame.
The negative feelings arising from childhood upsets and trauma energise or drive actions and thoughts that attempt to quell the internal pain and tension. The actions that occur are clearly the result of choice, or preference, in line with doing what brings about an anticipated or actual improvement in feelings. Some choose short-term solutions that bring about some temporary relief, but long-term harm to others, and also negative consequences for themselves. But with awareness, people who carry emotional burdens can improve the way they deal with such issues.
That is where understanding, community education, support and professional treatment comes into play.