Topic
Islamic law forbids killing non-combatants; genocide by any ruler, Muslim or not, is condemned by its standard.
What it means
The Quran says that whoever kills a person “other than for murder or corruption in the land” is as if he had killed all mankind (5:32). The Prophet forbade killing women, children and the old, and the early caliphs repeated it to their armies. The massacre of Armenians in 1915–16 was carried out by the Ottoman government of the Committee of Union and Progress, a secular nationalist party, and many Muslim families and some officials sheltered Armenians at risk to themselves.
What the sources say
Mass killing has been done in many cultures. Muslims were the victims at Srebrenica in 1995 and in Myanmar since 2017, and others have been victims of Muslims. This site discusses the case of Banu Qurayza in its own entry.