The seriousness of even a single case of pedophilia or child exploitation cannot be overstated. Not only is it ethical and moral to take it very seriously, but it's also the logical action because children are our future and if they are healthy and happy then the human race is healthy and happy.
There is no fixing the problem, but we can mitigate it. The first step would be, apparently, to educate the public because comments like yours still exist which is deeply concerning. The second step is up for discussion of course, but perhaps it would be useful to ban children under the age of N from appearing in videos for more than T amount of time or perhaps ban altogether.