Assalaamu `Alaaykum wa` Rahmatullaah wa` Barahkaatuh
I agree with sis Umm sufyaan and as it is clearly "obvious" as it is mocking Islaam, and something un-deniable. we shouldnt take such matters lightly or as a joke. Subhaan`Allaah this is only a characteristic of the hypocrite. This may just be my opinion but lets see what Allaah swt your creator has to say regarding this matter. He describes the hyprocrites.
"The hypocrites fear lest a Surah (chapter of the Quran) should be revealed about them, showing them what is in their hearts. Say: "(Go ahead and) mock! But certainly Allah will bring to light all that you fear." If you ask them (about this), they declare: "We were only talking idly and joking." Say: "Was it at Allah, and His Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) and His Messenger (SAW) that you were mocking?" [Surah At-tawbah ayah 64-65]
"The hypocrites, men and women, are from one another, they enjoin (on the people) Al-Munkar (i.e. disbelief and polytheism of all kinds and all that Islam has forbidden), and forbid (people) from Al-Ma'ruf (i.e. Islamic Monotheism and all that Islam orders one to do), and they close their hands [from giving (spending in Allah's Cause) alms, etc.]. They have forgotten Allah, so He has forgotten them. Verily, the hypocrites are the Fasiqun (rebellious, disobedient to Allah)." [Surah at-tawbah ayah 66]
Clearly in this ayaah Allaah speaks of the Kuffar as the hypocrites, lets not be one of them.
"Verily! This (the Quran) is the Word that separates (the truth from falsehood, and commands strict legal laws for mankind to cut the roots of evil). And it is not a thing for amusement." [Surah al-taariq]
"Verily, those who disbelieved in the Reminder (i.e. the Quran) when it came to them (shall receive the punishment). And verily, it is an honourable respected Book (because it is Allah's Speech, and He has protected it from corruption, etc.). (See V.15:9]"Falsehood cannot come to it from before it or behind it (it is) sent down by the All-Wise, Worthy of all praise (Allah).Surah Fussilat :41-42]
This ayaah speaks of how noble the Quran is as it is the words/speech of Allaah.
However, clearly the intention of the anti islaamic site (as thread starter mentioned)is to mock Islaam i.e.making fun of Islaam, and we as muslims shouldnt take this lightly. no matter how small it may seem, it is most certainly not a matter to laugh about.
Insha`Allaah this link can answer what i am trying to point if i do not make sense, please i recommend you check it insha`Allaah.
Forgive me if i sound harsh, my intention is not to, but to make something clear, if i have said anything wrong forgive me and correct me if so..
Wa `Alaaykum As-salaam wa Rahmatullaah wa Barahkaatuh