I have to agree with Joseph Farah's assessment. If you speak to the KKK you give them credibility regardless of whether you criticize their positions or not.
If a celebrity chooses to speak to the Ku Klux Klan, there is no question the Klan benefits from such an appearance – no matter how much the speaker might attempt to explain the differences he or she might have with the group's agenda. Justifying such an appearance by suggesting it's just another paid speaking gig would hardly mollify the criticism or negate the benefit the Klan received from the event.
Of course, no one in respectable public life would consider speaking to the Klan for those reasons.
However, I would suggest the ungodly, sin-glorifying homosexual agenda represents a far greater and far more imminent danger to the future of the United States than does the Klan's racist, ungodly and sin-glorifying agenda.
That's not to say we should never speak to or evangelize sinners – be they Klan members or homosexual activists. In fact, that's exactly what we should do. What we should never do is... validate their activism in any way. [my emphasis]
The homosexual network wants to be in the news. Controversy serves their purpose. That people are arguing about their legitimacy gives them credibility. That's what Coulter did and I agree with Joseph Farah that it was wrong.