"After hard fork, the price does not fall. Why?"
I think the price doesn't fall immediately because people don't know what to expect. If there was a lot of buzz that a fork was going to take a lot of users away then it would cause the price to drop. Without any negative press, most people probably don't even know about the fork.
Small spinners do not play a role, the price is held by big players, for which they only hold? who knows :)