Telepathy is far more subtle. There isn't nearly as much affect to observe as telepathy is being used. If I had that supernatural ability I would hide my telepathic ability and since I live in a world where telepathy isn't considered a real thing by most people it would be easy for me to hide it. Even if someone suspected I was telepathic there's very few easy ways to prove it. If someone tried to expose me as a telepath they would probably appear to be crazy and it would be my word against their word. Since telepathy isn't considered real people would more likely believe me.
The best part about people suspecting you are telepathic and then being reassured there is no such thing as telepathy is that once they are reassured the first thing people always think is, "Thank God he's not telepathic. If he could really read my mind then he would find out that..."
At least that's what I've read in fictional stories. Of course I don't know that first hand as a fact. Telepathy isn't real. Everybody knows that.