Your question asks if Twitter has a double standard.
The substance of the deleted answer was some details about a research project nicknamed "Truthy" from Indiana University, that tried to detect misinformation on Twitter. It had nothing to do with Twitter's moderation policies.
The answer in no way addressed the question, and off-topic answers aren't welcome here.
Note: The problems with the answer didn't stop there, but they aren't why it was deleted.
The answer started with an unreferenced attack on "the Left", on Obama's administration attitude to Free Speech, on the IRS, which was nothing to do with the question.
The answer made no attempt to show that this project had any effect on Twitter in practice.
The answer didn't present a balanced view of the project - it only quoted attacks on the project, without linking to the project itself, which contains copious resources explaining how the attacks were false and fabricated, and mischaracterised the nature of the project.