Why do people attack the Bible as promoting religious violence but deny that the Qur'an does so?

Usually because it is not “politically correct.” While many (usually Muslims and “liberals”) bend over backwards to find fault with the Bible, and habitually take things out of context to do so, they may question the premise that the Qur’an exhorts literal physical religious killing or violence, or even deny that it does.

Or they assert it is not really different from the Bible, even to invoking some study that uses the percentage of verses that “could be related to violence,” in each in order to attack the Bible. But which, besides the subjectivity in judging what “could be related to” means, this comparison - even if accurate - simply does not support that the Bible teaches literal physical religious killing or violence (henceforth PRV) for its believers today, for reasons explained below.

For the well-substantiated facts are that the Qur’an clearly commands and or exhorts PRV against adversaries, and, unlike the far, far, far larger Bible (the Qur’an is smaller than just the Christian New Testament), it lacks the context that could justify it, or restrict it to simply being for defensive purposes.

One can see here multitudes of Qur’anic texts on PRV and read a few from my collection here, and so let me briefly deal with some the basic differences between the Bible and the Qur’an.

• The Bible, with nearly 800,000 verses, provides extensive historically narratives in which its examples and commands of physical religious warfare overall exist, thus providing context. Whereby we see that:
• Commands to PRV were preceded by God making it supernaturally unmistakably certain that He was real, and was the one giving the commands. And which means (besides being the giver of life, and the only omniscient and omnipotent being who knows both the hearts or the people and the immediate and eternal consequences of their life and death, and can make it all work out for just purposes, cannot be judged for what He commands) that their commanded wars of conquest (as under Joshua) were not the results of some mere dream.
• These commands were limited to certain people and thus geographic areas, versus world wide jihad against all unbelievers who in some sense opposed them.
• Not all the the Bible records as examples means that God commanded it, which context determines.
• The Old Testament/Covenant promised as New Testament/Covenant, which was distinctly said would be Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the Lord.(Jeremiah 31:32)

And under which Covenant it was revealed that there would no longer be a physical kingdom, and thus its subjects would be using physical means of warfare to defend the faith and for the purpose of subduing those who attacked that faith. (Jn. 18:36; Eph. 6:12; 2 Cor. 10:3,4) and with nonretaliation (physically) to personal attacks being enjoined.

Thus we have zero examples or commands to PRV in the New Testament, and the only religious violence therein is by supernatural means.

In contrast:

• The Qur’an is basically a series of disjointed monologue statements from the god of Islam to Muhammad, and it overall lack the historical and or doctrinal context to determine their meaning, specific applicability and scope. As the Qur’an overall lacks this context then readers must be educated in how scholars interpret such, but in which there is conflict. And the lack of context can allow commands for PRV to warfare against ideological enemies, not simply physical ones.

Islamic scholar Aga Mahdi Puya is quoted as stating,
"Waging war against Allah and his Prophet means hostility against his chosen representatives, or deviation from his laws by overstepping the boundaries laid down by Him.. or attempts to undermine the cause of Islam and the overall interests of the Muslims."

• The commands to PRV in the Qur’an were not preceded by God supernaturally making it unmistakably certain that He was real, and was the one giving the commands. Instead, Muhammad began to have dreams, concerning which some tradition conveys that he was worried at first that they may be from the devil.
• The Qur’anic commands to PRV were not manifestly limited to certain people and thus geographic areas, versus world wide jihad against all unbelievers who in some sense opposed them.
• There is no new covenant in Islam, and while there are some brief quotes advocating tolerance, it is understood that these came from Muhammad's pre-Medenic suras when he was a minority in Mecca. Initially when he was weak (before Medina) he allowed more of peaceful co-existence by ways of treaties, etc., but when he gained power he progressively sought to enlarge his kingdom by force. History thus indicates that Muhammad's theology adapted to his needs.

Therefore there is no reason to not call out the hatred and violence in the Koran, or at least not if you are going to attack the Bible as promoting the same to its believers today.

But  there is still room at the cross for all who will come to God in repentance and faith, and trust in the Divine Son of God sent by the Father, the risen Lord Jesus, to save them on His account, by His sinless shed blood, and thus be baptized and live for Him. Acts 10:36-47