Watch: I don't like the tone of your comment. Now prove to me that you're not saying something in a tone that's not offensive to me. You can't. My feelings are authoritative "lived experience."
If someone disagrees but has a rational tone, I am more willing to voice my disagreements.
For me, tone effects my engagement with opposition, not whether or not I oppose something.
I would argue that without the "mean" tone, people might stick around twitter and have a discourse about their disagreements, and with the "mean" tone people are more likely to just bail and complain outside the platform.
Obviously we don't have a control group, so we have nothing to compare what twitter is doing right now against something else directly.