If your argument is that the people who where responsible where of Islamic belief, I still cannot find justification in your irrational protest. These groups of people are obviously extremists of there religion.
Fundamentally and philosophically, I completely agree with you. But on a practical level, I cannot.
My first point is that these people are, in fact, Muslims. Yes, they're radicalized. True, moderate Muslims do not want to acknowledge these people are part of their faith. But the simple fact is they are.
Think about what it takes to be a Christian versus, say, a Jew. For starters, a Christian must accept that Jesus Christ existed and was in fact the son of God - the messiah. Presumably, they must also follow certain dogmas within the religion, typically found in their respective holy book.
For those in the Islamic faith, the situation is similar. A Muslim would not accept that Jesus was the messiah, they would assent to the prophecies revealed by Mohamed, and they would follow certain particular dogmas.
Islam is a newer faith than either Christianity or Judaism, and like other religions it goes through certain phases. Would you call the Christians who committed atrocious acts in the name of God during the Crusades not real Christians? Of course not. They were simply following what the Bible told them to do - to kill infidels.
The Koran is quite similar to the Old Testament of the Bible and also has instructions for what to do about nonbelievers. In both texts, there are references to not suffering non-believers to live. So while our societal standards have changed since the Crusades, the messages within these religions is changing at a different pace.
But ultimately, the Islamic community must be sensitive to the feelings of those people where they want to build their Islamic center, and to the tragedy that happened - even though it was almost a decade ago.
My real worry here is that the response on a local level is going to be quite filled with opposition. The uneducated Americans who can't understand that most Muslims completely disagree with what happened on 9/11. With this opposition, there will undoubtedly be those individuals within the Islamic community who feel marginalized. And that's perhaps the first major step towards becoming radicalized.
On a practical level, this decision seems irresponsible.