Also, visible actions spread. Someone who posts a correction encourages other people to post corrections to other comments, while someone who PMs does not encourage that behavior. But it is also visible how many responses there are, so that people don’t overwhelm an individual with responses, while they might overwhelm with PMs.
Also, with visible explanations everybody knows what already has been explained and what hasn’t. If it were common to explain things via PM, some points would be raised multiple times while others not at all, depending on the number of readers estimating enough high probability that they are the first to comment on an issue and thus not wasting their time by making duplicite comments.
Also, visible actions spread. Someone who posts a correction encourages other people to post corrections to other comments, while someone who PMs does not encourage that behavior. But it is also visible how many responses there are, so that people don’t overwhelm an individual with responses, while they might overwhelm with PMs.
Also, with visible explanations everybody knows what already has been explained and what hasn’t. If it were common to explain things via PM, some points would be raised multiple times while others not at all, depending on the number of readers estimating enough high probability that they are the first to comment on an issue and thus not wasting their time by making duplicite comments.