> Section 230 was about hosting user comments though.
No, 230 is not about “hosting”, its about (what would, absent Section 230, legally be) publishing.
> Microsoft, for example, can’t publish an article on Microsoft.com defaming people and cite section 230.
It absolutely can, if some other “information content provider” submitted the information in it, because they are not legally it’s publisher in that case; that is the central point of § 230. [0]
The question here seems to be what happens when the way interactive computer services relay information from other internet content providers is by farther from relaying distinct externally provided content units that may be mixed, ordered, promoted, demoted, or suppressed by an algorithm, and instead synthesizing new content units from externally provided and actively sourced information.
But the 230 safe harbor doesn’t focus on content units (by any name), it focuses on information, so as long as the defamation comea from information provided by another “information content provider”, no matter what algorithmic means and content structure goes into presenting it, it would seem squarely within the safe harbor.
When defamation arises not from a particular third-party source material, but only from the algorithmic synthesis, things get trickier, but if its all third partt information (even separate pieces of it that the algorithm presents together) it still seems within the safe harbor.
When its (in whole or in part) information Microsoft actively sourced or that the MS-operated algorithm created ex nihilo (hallucination) that makes it defamation, though, that would seem to be Microsoft’s liability.
[0] 47 USC § 230(c)(1): No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.