Why would they? 1. Astroturfing is marketing and in general people want information about products and services. 2. To be good, moderation must be done by han

Why would they? 1. Astroturfing is marketing and in general people want information about products and services. 2. To be good, moderation must be done by hand. That's expensive. Platform users don't want to pay for it. Moderation done on the cheap leads to false positives and false negatives. Those feel like injustices and piss-off users. 3. Astroturf is asymmetric. Astroturfers have strong financial incentives to work toward bypassing filters. Platforms have large attack surfaces. Patching every possible small hole creates friction for good faith use. The Usenet is still with us in spirit. Good luck.