The objection identifies real violence and cultural loss in Muslim history, and it should not be answered by pretending that every conquest was purely peaceful. But conquest by later Muslim rulers does not by itself prove that Islam is false, nor does it show that conversion everywhere was forced.
What the objection gets right
Muslim armies did establish a large empire after the death of the Prophet Muhammad (PBUH). Persia, Egypt, Syria, North Africa and other lands came under Muslim rule. Some rulers abused power, imposed unjust burdens, destroyed institutions, or pressured minorities. In particular cases, forced conversion and persecution occurred. Those acts should be condemned, not excused simply because the perpetrators were Muslim.
The strongest version of the criticism is therefore serious: if Islam teaches that armies must impose its religion, then its claim to be divine would be morally and intellectually weakened. Nor should descendants of conquered peoples be told that historical political domination, by itself, creates a religious obligation.
What the Quran actually requires
The Quran distinguishes between accepting Islam and living under Muslim political authority. It states:
There is no compulsion in religion. Truth stands clear from error.
Quran 2:256
It also commands justice toward those who do not fight Muslims:
Allah does not forbid you from being kind and just to those who have not fought you because of religion or driven you from your homes. Indeed, Allah loves those who act justly.
Quran 60:8
Quran 9:29 does mention fighting certain People of the Book until they pay jizya. Classical Muslim scholars understood this within the framework of states, warfare, and a protected non-Muslim population - not as a command to convert every human being. Jizya was a tax associated with exemption from military service and protection by the state, though its administration was sometimes humiliating or unjust. The verse and its legal interpretation deserve moral scrutiny, but reducing the entire doctrine to "convert, pay, or die" ignores both its historical setting and the range of legal conditions discussed by Muslim jurists.
Empire is not the same as conversion
The Prophet Muhammad (PBUH) did lead military expeditions and governed a state. Islam therefore does not teach absolute pacifism. Yet the later conquests were not simply one uninterrupted campaign personally launched by him, nor did they automatically erase local religions. Large Christian communities remained in Egypt, Syria, and North Africa for centuries. Persian language and literature survived and flourished; local customs often entered Muslim societies. In many regions, including parts of Africa and Asia, Islam spread gradually through trade, teaching, marriage, and local rulers rather than conquest alone.
That does not make imperial rule innocent. It means the historical evidence is more complex than the claim suggests. The conquests establish that Muslim rulers, like other rulers, could commit injustice; they do not establish that the Quran is false or that every Muslim conversion was coerced. Islam is judged by its revelation, while Muslims are accountable for how faithfully they obey it.