That is very damning to Twitter as far as 230 goes - there is NO way that could happen without editorial decisions overriding or directing any algorithmic determinations.
Google’s entree to the search engine space was driven by their introduction of “authority” into ranking. If you had a domain that had strong standing you got ranking. If you were linked to a big site you got authority.
NYPost.com has authority. How it all of a sudden could be deemed “spam” MUST involve some kind of human intervention - otherwise their systems would be acting erratically all over the place all the time.
Then ... there is a SECONDARY determination being made by denying a “.gov” domain - there is default authority assigned to and given to “.gov” domains - meaning they are (should be) assumed legitimate.
Twitter blocking or treating “house.gov” in this way and manner is not viable in any purely algorithmic way - it MUST be driven by some human intervention & editorial determination at some point to the extent that it’s now tainting legitimate sites with given authority.