I am sceptical of some of the points in the linked text as well. The author mentions that there are cultures in which parents masturbate their children, but that isn't obviously harmful. Yes, an example was cited where the masturbation in question was done in a harmful and painful way, but that isn't to say that it must always be so. Young children have been documented to occasionaly masturbate even on their own, so why is it that adults helping is immeaditly abuse? And citing

"co-sleeping," with parents physically embracing the child, often continues until the child is ten or fifteen

as an example of "abuse" is getting us into the ludicrous territory. Embracing your child is abuse! The author also makes pretty big leaps of correlation and causation:

Boys in many New Guinea groups today, for instance, are so traumatized by the early erotic experiences, neglect and assaults on their bodies that they need to prove their masculinity when they grow up and become fierce warriors and cannibals, with a third of them dying in raids and wars.

Of course, there are also plenty of valid points about real sexual abuse that does take place, or has historically taken place.