Sadly alot of them do this but I think it will not be a concern for bitcoin in the long run because there are more people getting introduced to bitcoin everyday than seeing the ads of icos trying to dethrow it.
They laughing because they don't know anything about the bitcoin, they don't have an iota of information about bitcoin. If they have knowledge about the bitcoin certainly they wouldn't have taken it lightly. So stop caring about such class of people just try to concentrate more in bitcoin.