This is no surprise at all. The Left and the Islamic supremacists hate the freedom of speech. They cannot abide dissent. They cannot refute our arguments, so they shout us down, demonize us, defame us, and deface our message.
UPDATE: Pamela Geller makes an extremely important point: "In a rational society, [this vandalism] would be looked down upon, but more importantly, the defacement is a metaphor for this entire conversation. Hundreds and hundreds of anti-Israel posters ran all over the country. Not one was defaced. One anti-jihad poster goes up, and it's defaced within an hour, while its creator faces defamation, smears and libel. Islamic supremacists and leftist thugs criminally defaced these ads within an hour. This is a physical manifestation of the entire conversation, or lack thereof. Anyone who speaks about jihad and sharia is attacked, defamed, destroyed -- just like these ads. This is exactly what’s happening in the media regarding jihad coverage in general. Anti-American, anti-Israel, pro-sharia hate is all over the airwaves, but anyone who dares to speak the truth about Islam and jihad in the media is immediately smeared and defamed. You can't have this conversation in the media, any more than I can present these pro-Israel ads, and receive any semblance of fair treatment."