I don't think that Seraph is making the argument that Western civilization is some sort of bogeyman. I know I haven't made that argument. The argument she is making - one which can be backed up by simply looking at a map - is that the evils committed by Western European civilization are unrivaled by those of any other set of cultures in scope and power.
Western civilization has done a great deal of good in the world. I'm part of it - a white girl in North America, born in the American South and living in the Pacific Northwest. I think I'm pretty awesome, and I'm the tip of the iceberg there. But that doesn't change the scope and degree of evil in our background.
Genocide across literally all human-inhabited continents. The theft of land and resources. The drawing of national boundaries specifically to produce regional ethnic and religious tension and allow further meddling. Colonialism and the destruction of native cultures. Conversion at the point of a sword or the end of a gun. Intercontinental, intergenerational chattel slavery - not the sort of "we enslave debtors and war prisoners" known throughout the ancient world, but the mass relocation of entire ethnic groups and their coercion into brutal, body-and-soul-destroying work for generations with no real hope of escape. Deliberate, systematic destruction of natural resources in an effort at defeating in war an enemy whose land the war is being fought on and who had no chance even if the war was conducted in a purely conventional way.
Those things are as much a part of my cultural heritage as the Declaration of Independence's unique statement that people are equal, as the beauty of Versailles and Vienna, as the first touch of humanity on an alien world, as close-up pictures of Pluto, as a game that lets me interact with worlds that share the imaginations of myself, my friends, and my loved ones with specific, predictable rules that allow our souls to craft stories and people and universes together in a way nothing else ever designed ever has. I think it is an act of intense intellectual dishonesty to enjoy the fruits of these good things without also confronting the intense, unrivalled, and (this is the way it is most undeniably unique) global evil done along the way, in the name of the same set of cultures that produced these good things.