One reasonable answer is that FB/Google/etc. should donate or donate more (Google is called out as donating already) to these organizations. I think another reasonable answer is that technologists donate our time, perhaps as 20% projects or as sabbaticals to these orgs and help them modernize.
It does seem Congress (per the NYTimes article I linked above) isn't doling out as much funding as we would like to see.
And, in fairness, children are being harmed here, and at an incredibly alarming rate. Please do read the NYTimes article. The Times is, IMO, a fairly responsible actor in truth telling.
One is our job that we are directly and morally responsible for (like a civil engineer being responsible for having a bridge not collapse at a load of >2 cars), the other is not. Call me callous, call me cold, but that is not explicitly up to us, we can't be under the delusion that we are the one key to everything and anything. It wouldn't make sense to have a "quick-release" button forcibly installed on all bridges that would cause an instant collapse if triggered "because countless children that are victims of human trafficking are taken over bridges everyday."