This change would substantially benefit large providers at the expense of smaller providers.

AWS can afford to be sued for hosting a forum or the costs of a boycott for hosting Stormfront - a smaller provider could easily be wiped out.

Edited to add the following.

Most of this post was wrong. ttt0 is right that section 230 protects providers in the cases I mentioned. TIL about the scope of section 230 provider protection.