The algorithm is not looking for toxic content to amplify. It's looking for content that would attain the most engagement of its users. If you consider the posts to be toxic, then maybe you are in a minority.
Everyone in this thread but you understands that the even if they are not optimizing for outrage, by optimizing for engagement you implicitly (and objectively) serve more negative/polarizing/divisive content.
Yes it does. The amplified content is just content that attracts the most engagement. It is not a reflection on how "toxic" the content is. If someone considers the post to be toxic and does not engage with it, then that person is not the majority of users.
This line of argument is exactly why I think intention (mens rea) should be abolished from the legal system completely. Outcomes matter, intentions don't matter. If you don't want to put someone in danger, don't do the thing that may put them in danger. It's up to you to anticipate the consequences of your actions.
It really doesn't matter what the algorithm is meant to do because it's very obvious the material consequences of what it does.