The Great Barrington Declaration was never censored. Younes, who works for a Koch-funded litigation group (Koch groups have spent the pandemic fighting against public health) is trying to paint valid criticism of an unscientific document as censorship.
Official Trump White House policy mirrored the recommendations of the declaration and its authors were treated like VIPs.
The goal here is to harass and silence criticisms of right wing pseudoscience to force parity with scientific consensus.