Quick correction. The warp was turned from a calm reflection of reality into hell not by the modern galaxy but the war in heaven which took place at some starting point up to around 68 million years ago. The Aeldari certaintly did not help the warp by birthing Slaanesh but the vast damage done to the warp was done by a conflict so vast it makes the modern fighting look like a water gun fight.
Holy logical fallacy batman. Ad hominem much?