Did you ask yourself why do they all "heal" the same "disease"?
Why are they always asking for pain in the back and so on. And when someone says that he feels a pain now and then in the back they make him sit down and look at his legs and then they "discover" that one leg is shorter then the other.
They don't stop people that are limping, but people who look very healthy. Also, when people are asked if their back and articulations don't hurt from time to time, of course they will say yes. But that is normal. It doesn't mean you have a disease. So the "healers" play on these things. They are also very bold and confident, while the people on the street are shy and confused because some strangers are not only talking to them but also filming them. So, when they ask the people if they feel better, the people will genuinely say "yes" out of courtesy or because they were brought into believing that they felt pain before (when in fact, they didn't).
These "healings" are nothing more than tricks. I'm sorry, but it is the truth. Jesus Christ performed miracles, not tricks. He didn't run in Jerusalem with a camera after him to show people how he grows back legs, and neither did the apostles.