The right to burn a Koran is not the main issue. The key issue is whether we are free to conduct research, and to publish conclusions like this:
[Sven] Kalisch, . . . scandalized the Muslim world with a 2008 paper claiming that the Prophet Mohammed was a figure of myth . Citing the work of Western Koran critics, Kalisch claimed that the prophet's life was the fabrication of 8th-century apologists:It is a striking fact that such documentary evidence as survives from the Sufnayid period makes no mention of the messenger of god at all. The papyri do not refer to him. The Arabic inscriptions of the Arab-Sasanian coins only invoke Allah, not his rasul [messenger]; and the Arab-Byzantine bronze coins on which Muhammad appears as rasul Allah, previously dated to the Sufyanid period, have not been placed in that of the Marwanids. Even the two surviving pre-Marwanid tombstones fail to mention the rasul.
Islam, he concluded, was a revival of the old Gnosticism expunged by Christianity and embraced instead by the Arabian tribes.