Re: I think my reading comprehension is going downhill
No, you're not. I'll re-word what the article said:
In the population of all sampled parents, 43% felt the negatives of social networks outweighed the positives, 26% felt that social networks provide more benefits than harms, and 31% answered "something else".
In the population of sampled parents who allow their children on to social networks, 26% felt the negatives outweighed the positives.