Salam. I felt called to say what I think about the issues regarding the use of word Allah by Christian churches. Need be as I see this issued are being overplayed to incite hatred and anger for interreligious harmony & political agenda.
First, there is no suggestion by Allah himself that his name can be called by just the Muslim. Allah is the Creator and Sustainer of the Universe. By this logic, Allah is definitely Owner of everything. Jesus Christ do not create Christian believer, Siddharta Gautama do not create Buddhist believer, and surely sun do not create sun worshipper. However, Allah does make suggestion what we can call him:
Say: Call upon Allah or call upon, the Beneficent God; whichever you call upon, He has the best names; and do not utter your prayer with a very raised voice nor be silent with regard to it, and seek a way between these(17:110). These means we can call him Allah, Ya Rahman, and Ya Rahim, but whichever He is called, he belongs to beautiful names. The previous cited sentence is the famous one that derived Asmaul Husna(Beautiful Names of Allah) I recall one hadith which sounds like these “Allah is Good and anything Good is associated with Him”. Therefore, it is a dumb suggestion that Allah is a name that is a franchise of Muslim, a God to Muslim specifically.
Second, we can refer to history. In its early Islamic civilization, Muslim has remarkable commitment to understanding and coexistence with the People of the Book. Islam clearly grants respect to Christians and Jews: Say: O People of the Scripture! Come to a common word between us and you: that we shall worship none but Allah (Aal-Imran, 3:64) and in al-Ankabut Allah says: And dispute not with the People of the Book but say “We believe in the Revelation which has come down to us and that which came down to you…our God [Allah] and your God [Allah] is One, and it is to Him we bow (al-Ankabut, 29:46). From here, it is obvious that Allah is One, none comparable to other so-called God. I could also remember the writing of Mufti Perlis; which he states the religious tolerance shown by Prophet Muhammad (pbuh). Muhamad allows the Christians and Jews to use the sentence (Bismikallahhumma) translated (with your name Allah).
Third, this issue could also serve a cynical message. Most of our malay Muslim often like to call God rather than Allah. The use of word God rather than that of Allah, especially by Muslim, shows very distant, unfriendly relationship with Allah. Alas, Allah creates this issue so to serve the reminder to Muslim. So this is a signal to call him by name Allah. God can refer to everybody below Him, but Allah refers to none except Allah, the One. Despite their reasoning that when they say God, they actly mean Allah, it is no excuse. It is matter of choice between knowing what is good and what is better.
Despite my points, I am not opted to either supports or forbid the usage of word Allah. On the other hand, I agree with the opinion by Khalid Samad and Marina Mahathir. Regarding marina mahathir opinion, it really attracts me. If muslim, being the true religion believer, why afraid of such little things? If you understand who Allah is, there is really no issue here. It is ok for the Christian and Jews to use it, if they have a good intention may Allah blessed them. It really depends on the intention, if they think of bad intention to use it; it is considerable that we endeavor to disallow it. This issue is simple, simple really. I believe the outbreak had been invented by none other than religious extremist and politician.
p/s: The Muslim better focus on a surefire things that are disallowed by Allah: Melodi( for gossiping, backbiting, scandalmongering which is stated by Allah in 104:1), Akademi Fantasia (for promoting entertainment that tends to mislead the youth from remembering Allah), and so MANY obvious things.