If you were molested as a child, the primary reason YOU were molested is someone who WANTED to molest you had access which gave them opportunity to do so.
That's it. That's the entire explanation.
And 99 percent of that is outside of the control of most kids. Most kids have lives dictated by the choices of adults and they have little say in their own lives.
Child molesters routinely choose professions or hobbies that give them access and opportunity. They actively look to get on the short list of "trusted adults" that OTHER adults trust so OTHER adults will give them access to kids and opportunity to molest those kids.
And most adults will not respect the wishes of their children to not be left alone with certain people.
My kids were never molested in part because from an early age, if they didn't LIKE someone, I didn't leave them with them.
Kids have no problem expressing their FEELINGS, though they may have no ability to articulate WHY they are unhappy. They don't hesitate to cry, scream, tantrum or pout.
Most adults just ignore that much of the time.
As an infant, my oldest son was very sociable and loved attention. There were only two people he refused to go to:
1. My brother, who raped and molested me.
2. My brother-in-law that I felt was a creep. (He later tried to kill my sister for divorcing him. Can't imagine WHY she would leave.)
When my brother-in-law offered to keep my baby so me and my sister could go shopping without the hassle, I told him "No." and made polite noises about "Babies! They got no sense. Who understands them? No clue why he doesn't like you. Maybe it's the mustache. My brother has a mustache and he won't go to him either. I will just take him with me."
If my kids didn't like a babysitter, I found someone else. Full stop.
I was fortunate to be able to be a full-time mom for a lot of years, which made that relatively easy. But if you want your kids safe, you should do your best to account for the feedback they give you about liking or not liking certain people.
They know better than you how that person treats them when you aren't around.