The tract was just a rearticulation of the Puritan evangelical program. Are you saying that our fore-fathers were tricked into Christianity? If one "lathers up" is he preparing for salvation or is he performing his own salvation?
The point of the article is not why you would or would not lather up. The point is that if you refuse to lather up then you are preparing for your own damnation. The point is that regardless of the reason why you respond to the gospel message, the fact of the matter is that if you are to be saved, you MUST respond to it. You must do what the gospel says. You must believe. Responding insures your salvation, while refusing to respond insures your damnation.
So if you don't respond to the gospel, the gospel does you no good. The fact that some people refuse to bathe is no reason to believe that soap is not effective. Similarly the fact that some people refuse to heed to gospel message is no reason to believe that the gospel message is not effective.