So?
Fred Phelps is a minister of the Christian faith but that doesn't mean every Christian in the world celebrates the 9/11 attacks and jacks off over the thought of dead soldiers. Muslims, like Christians, are not a unified group so what makes you think that some obscure radical cleric from one of the most religiously conservative countries on Earth is in any way representative of the majority of Muslims?
Don't be ignorant. The vast majority of Muslims are moderate, ordinary people. If you went to a coffee shop dressed as Mickey Mouse you'd succeed in looking like an idiot but nobody is going to be offended.