I am not sure that it matters 'why they censored'.
Put it another way, I do not think it matters if they applied their own ToS rules correctly, incorrectly, selectively or whatever.
I am not sure that their terms of service, allow them to claim protection under 47.230 [1]
I am sure that the position that the fed government investigators will take.
If Twitter folks (or their crowd-sourced moderators, or committees) gray-out/remove/comment on/hide/edit content that Twitter claims 'is not theirs' -- then it is hard to imaging they are compliant with the 'non-publisher' protections of section 47.230.
Imagine if one is a for-profit business, claiming tax code for a non-profit organization.
Their Terms Of Service mentions: 'Making the world better and being charitable. We do not do business with bad clients'.
Does that make that business less criminally liable for claiming taxes of a non-profit?
To me it does not.
That's not why Twitter "censored" the news story. They removed links to a story that violated their published policies.