Facebook literally heavily contributed or at minimum enabled and amplified at least one genocide (2017 Myanmar). That is the total opposite of "really not causing harm".
Plus they implemented "Organic Reach" where the bands I followed posted the flyers to their shows and Facebook only distributed the posts to ~10% of users subscribed to the band, so over and over again I would see a flyer for a show that happened 2 days ago. Deleterious to culture at large.