Paedophiles are specifically those attracted to prepubescent children, so anyway the label is incorrect despite its current popular usage.
But that said, the rest of the article is typical of this sort of attitude, that conflates "knew what she was doing" with being somehow responsible for not only her actions, but his as well. What he was doing with her was wrong, and he knew it, or should have known it, and been responsible for stopping rather than egging her on.
But quite apart from that, there's the misguided view of nature of the girl's responsibility. She was fifteen, young, naive, sexually charged presumably, egged on by her friends, and in a cultural setting where such behaviour was normalised. In what meaningful sense under those circumstances is she really in control of the situation? It doesn't make sense at all.
Yes, there is a problem where young girls in particular could be said to "throw themselves" at the rich and famous. Yes, it has to be acknowledged. No, it doesn't have to be blamed on the girls themselves. Without falling back on that hackneyed phrase, "society is to blame", what is true is that blaming and shaming the girl here solves nothing. Far better to ask how she ended up in that situation in the first place. And what the hell Adam Johnson was thinking. To be fair to Katie Hopkins, she doesn't exactly let Johnson off the hook in her article either.