The law that grants Twitter immunity for targeting conservatives
47 U.S. Code § 230 - Protection for private blocking and screening of offensive material
(c) Protection for “Good Samaritan” blocking and screening of offensive material
(2) Civil liability No provider or user of an interactive computer service shall be held liable on account of—
(A) any action voluntarily taken in good faith to restrict access to or availability of material that the provider or user considers to be obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected