When she eventually describes herself as being 'trapped by love' the gears start to slowly turn in his brain as he tries to process the situation. When Daphne throws herself at him again and again and again, he's completely oblivious to her advances, and it's not always because he's distracted by traps, he simply can't comprehend Daphne's actions and intentions. This drove him into the world of 'traps' as his child mind concluded that maybe mommy wouldn't have run away if he had been able to trap her and keep her in place so she couldn't run.
He was raised by a man who was not his father, and who constantly lied to him and told him that his mother ran off when he was an infant. Click to shrink.Nah, it's more than that, Fred's seriously damaged (in Mystery Inc).