Under Title VII, the ADEA, and the ADA, an employer may not “discriminate against any of his employees... because he has opposed any practice made an unlawful employment practice by this subchapter ....” 42 U.S.C. § 2000e-3(a); see also Napoleoni v. New York City Dep't of Parks & Recreation, No. 18-CV-2578 (MKB), 2018 WL 3038502, at *4 (E.D.N.Y. June 18, 2018) (reciting similar language for ADEA retaliation claims