A public narrative, which was visible in the recent terror attack in Christchurch that, even though various wars/battles among various world powers ravaged Europe, and various invasions also took place throughout its history, somehow the Ottoman invasion and regime is remembered and felt very strongly in the non-Muslim world as if Communist, Nazi, and Fascist were somehow much better, or in other words, much acceptable than the Ottomans. Also, genocides of Bosnia are not much talked about, as if that was not enough for Muslims to pay the price.
This is like saying, "Even if he killed 6 million Jews or 2 million Ukrainians or a few thousand Bosnians, he is our homeboy. So, just forget that."
One point could be: Ottomans never either accepted or paid the price for their atrocities. They might have never accepted but neither did the Russians or Serbs or Croatians. On the other hand, Ottoman empire was invaded and split, and modern Turkey was a de facto ally of the Allied forces during the WW2.
Another point could be, that narrative is limited to some extremist groups, not the mass population. This is simply not true. Going through comment sections of various social media platforms, news sites, and so on could easily refute this argument. Also, the rise in minority persecution in various developed countries could also be added as a proof.
So, my question is, What is the origin of this narrative?