Haggard did wrong.
He preached doing right and did wrong behind the scenes. The leftists have no problem with men who cheat on their wives with other men - e.g. McGreavey in New Jersey - just so long as there is no judgement, no morality or no ethics involved.
They're enjoying this specifically because Haggard said that one shouldn't but he did in secret. They want no curb on moral degradation. That allows them to pursue whatever perversity that they choose. And that is the overall reason for attacks on Christianity. Haggard's actions are completely acceptable, even desirable to the left. It merely helps them with their agenda.
There are also sociopaths/criminals/adulterers among police, FBI, CEOs, liberals, Hollywood stars, and adored athletes, and even Presidents. One should not be surprised that there are among ministers, especially in areas where big money can be made.