Because these statistics are not accurate, it lacks too many variables, its like using the racial crime statistics in an argument and ignoring all the other variables that goes into what can cause someone to commit a crime.

For example in this statistic that you are bringing up gives the man a fair advantage to win custody if he requests but fails to address what would make a father require full custody and take the kids from their mother in the first place, does a father only ask when he sees abuse? Mistreatment?

Also it fails to account that mothers spend more time with their children due to fathers being the main providers of the family which would keep him out of the house longer, which means the children sees their mother as the main parent while the father is the supporting parent, changing this behavior is usually a big issue for the kids.

When I did my MS in the first 2 weeks of the course was the professor going on about how easy and dangerous it is to mislead people with stats.