While that’s true, I’m not sure how many people are using Mastodon that way and if that’s actually the main concern. In the end it still is meant to be a public platform. Not on the same level of “private messages and photos” where most people would probably be very concerned.
Of course cooperate social media isn’t the only harmful social media, if anything it might be the most civil one for its scale, simply because they’re trying to sell ads next to the content so the content can’t be complete garbage. They also have a bunch of other incentives that ultimately make it a shit experience for everyone, but there is an incentive to moderate.
Something to remember is that it isn’t the company producing the harmful content. It’s people.