The post was in now way offensive, it contemplated real issues. Maybe it should have been written in a slightly lighter way. Still, the immediate visceral “ashkenazi lives matter” reaction was way inappropriate and shows that any community can fall low.
Maybe part of the reason that most are accustomed to Reform/MO/non-Jewish views and understand what they hear. In this case, a traditional Sephardi view was not on their radar and sounded unfair. General musar advice is when you hear an accusation – even if it feels unfair, stop and contemplate and try to find a morsel of truth even in the most unfair accusation. If you find it, you will benefit from it even if the accuser did not intend to benefit you (which is not a case here).