The problems I have are two-fold.
First, resources (particularly financial) are a zero-sum game. If the problem is over or under represented, some other problem that could impact more people or impact others just as harshly will get a disproportionately low share of attention/finances/problem-solving. Drug abuse among students is one that comes immediately to mind. Having good statistical data to understand the actual scope of each problem is key to being able to distribute resources appropriately.
Two, if you present numbers that seem unrealistically high, people will tune out the important part of your message. The 1-in-4/5 number that's floating around is a great example of that. There are studies that can be manipulated to such conclusions, but they are so twisted in their data interpretation that no one who understands how to read academic papers actually believes them. Activists bank on the shock value, but if and when someone shows how convoluted the process is to actually get to those numbers, it does more harm than good because most who once said, "Wow, that number is unbelievably high" then think "Wow, I was right that it was unbelievable - why should I believe anything else this advocacy group tells me. If they have to lie about their numbers to even get me to care, it's obviously not that big of a problem." Fool me twice, shame on me and all that.
The solution to both of those issues is to find good data and go from there. Unfortunately, people on the advocacy side and the lunatic fringe on the other side are so invested in their respective corners that no one is interested in actual data at this point.