Principle of audience benefit
About
The principle of audience benefit is a pragmatic and rational reality of debate which notes that you cannot effectively advocate for something that is known to be harmful to your audience (those whom you are attempting to convince).
In other words: if you are arguing for something which is against the interests of your audience, you lose the argument as soon as this becomes clear. You cannot win the argument by insisting that the audience's interests aren't important.
While this might seem obvious when stated thusly, it nevertheless remains a fact that arguers often try to dismiss the interests of their audience as irrelevant – presumably in the service of some greater good, though the beneficiary of this greater good is generally left unspecified.
Example
libertarianism
This is particularly common with certain libertarian/frontierist arguments that are based on the assumption that individuals will see themselves as independent of society and hence accepting of the idea of personal benefit at the expense of society -- when in fact the audience accepts no such premise, and is typically arguing the opposite position (i.e. that benefit to society benefits everyone).
Related
The principle of audience benefit is a corollary and expansion of Stross's principle.