Why do the Beatles appeal to family friendly people and not heavy metal?

Why do the Beatles appeal to people who are so family friendly? But
heavy metal doesn't? What is wrong with Heavy Metal? Are they against
what heavy metal stands for or what? And I am not talking about modern
day heavy metal. I'm speaking of 1970's and 1980's heavy metal and
hard rock such as Ratt, Led Zeppelin, Iron Butterfly, Dokken, and the
list can go on and on. Also if you notice during the summer you will
have festivals. These festivals cater to being family friendly. They
hardly ever book bands that play classic hard rock but seem to take a
liking to cover bands that play Beatles music. Why is that?
Charles Mansons favorite group was the Beatles? Big freaking deal.

We are talking about the view of music in today's day and age. When
the Beatles came out they were considered rebellious and "Bad" to the
family friendly people back then.

Times a different now and you have alot more family friendly people
listening to the Beatles than Ratt or Motley Crue or Metallica.