I'm surprised no one brings up The Monolith Deathcult, who gained some notoriety for their feud with the morons at Metalheads Against Racism a few years back.
They conspire in their caves in their envious world of emptiness
Preparing for Jihad to obey their desert god
They murder for belief to deflower 70 virgins
These "brave" Mudjahedeen brought Gaza in darknesss
Their God is a worm baptised in the blood of the prophet
On the hills of mount Sinai we meet in Armageddon
The laws of the Sharia will not impress upon us
Your holy army, blotted out, pounded into sand
In the napalm sea, the suns of Ismael bathe in flames
Is this the prophet's breed? Headless corpses return to dust
They have defiled our graves, their punishment will be endless
Our blistering napalm rain wipes them from the face of the earth
We desecrate the black stone
Slayer of Jihad
We do not obey their wretched desert God
We are impure
We are unrepentant, your final blasphemers
We distort your image of God
The walls of Jericho will fall again
We root out the seeds of the Mudjahedeen
The golden dome shall return to sand
"The blood of your forefathers shall be shed on mount Arafat
The bastard sons of Abraham shall never rise up again"
The laws of the Sharia will not impress upon us
Your holy army, blotted out pounded into sand
The pest of Arabia shall not overwhelm us
Their lustful prophet desecrates the innocent virginal skin
In my dreams I go back to the forest of flesh
Where the Ottomans lay slain before the cathedral of death
The sacred black stone, the black seeds of Jihad
We blaspheme in the presence of their backward desert God
Impalement is delightful, let us urinate on foes
We hammer the stake through the back of their throats
Face the flesh horizon, destructor, misantrophe
The corpses of the impaled Turks penetrate your hopes
They have defiled our graves, their punishment will be endless
Our blistering napalm rain wipes them from the face of the earth
We desecrate the black stone
Slayer of Jihad
In addition to that, much NSBM or nationalist metal (anything with an anti-immigration message, really) could be construed as being anti-Muslim. I think metal in general has more of a problem with the actions of Muslims, as opposed to Christianity where the ideas are being attacked. Without the immigration of Muslims into the west and the tension that results I think the amount of anti-Muslim metal would be even smaller.
1- Do you believe that your religion is a choice you make?
Ultimately yes, however some religions are harder to get out of than others, while others are impossible to get into.
2. Do heavy metal bands target Christianity because they mean it, or just because they can?
Some do and have done it for shock value, although even the ones that do it because of the metal tradition have some level of honesty to it. Christian metalheads (and sympathizers) tend to paint anti-Christian metal as a joke or insincere, basically to resolve cognitive dissonance I imagine ("They don't *really* hate me and my religion" or "They only hate my religion because they don't understand it, if they got to know it better they would realize that their arguments are wrong").
3. Do you think the criticisms usually leveled at Christianity by heavy metal bands also apply to Islam?
No, Islam has not been a major force in the history of the western world and the historical and cultural differences are vast.
4. Given current world events and how they are affecting especially metal-prolific Scandinavian countries, do you expect more anti-Islam themed band names, album names, and song titles?
Absolutely, especially out of the NSBM scene. As Muslim immigration to western nations increases and cultural tensions rise (witness the recent events in France, for example) anti-Muslim and anti-Arab sentiments are likely to grow. I think this will be seen outside of metal in punk and rock music as well.
7. Do you think Century Media or The End Records would sign and release albums by a band called Rotting Mohammed?
If the profits to be had outweighed the potential repercussions, certainly.