I think you are still failing to understand section 230. 230 does not regulate the relationship between two businesses. It is 100% irrelevant to the relationship between AWS and Parler. It had no effect, and if it's repealed, it would have no future effect on AWS kicking other businesses of their site.
Section 230 limits who can sue Parler for content published on their site. Without 230 Parler (and Free Republic) would be worse off, because they could get sued for anything the users post. The First Amendment isn't a liability shield. The simple question is whether sites like Free Republic and Parler should be liable for 100% of the things said on the platform. If they are, they will be driven out of business. Is Jim Robinson the editor of Free Republic and legally responsible for what you say? That's what repealing section 230 would do.
Section 230 is not and cannot be the be all and end all with respect to (allegedly) protecting platforms from liability with respect to content providers, no matter its merits or deficiencies. And it ought to have applied to Parler since AWS threw them off the web on the basis of claims with respect to content creators.