This killed my budget on a display campaign I setup last year and there seems to be no easy way to mass exclude these channels. I even tried setting the content of my ads as not family friendly but still found this didn’t solve the problem for retargeting campaigns.
That is exactly why i dont use display. Eventually you can set reach with frequency set to 1 and lowest cost per view possible. And each our ban all junk. There is a lots of it, so it is impossible to remove all. But after two, three days, you get a nice list of websites where actually you want to display ads. Than you can show ads only on these pages.
Other way is to use keyword setting. Not as topic or observation, but page containing a keyword. With good set of keywords it is possible to rule out baby clicks
