The fact that some event happened outside of work hours by no means disqualifies it as legitimate harassment. We should absolutely not be disparaging people for invoking this protection. Think of all the vulnerable groups who may be less likely to speak up after some shitty behavior if we start shitting on people for invoking this protection.

A hostile work environment claim may include conduct that occurs in a work-related context outside an employee’s regular workplace.[219] For instance, harassment directed at an employee during the course of offsite employer-required training occurs within the “work environment,” even if the training is not conducted at the employer’s facility.[220]

Example 53: Harassment During Off-Site Employer-Hosted Party Was Within Work Environment. Fatima’s employer hosts its annual holiday party in a private restaurant. One of her coworkers, Tony, drinks to excess, and at the end of the evening attempts to grope and kiss Fatima. Although Tony’s behavior occurred outside Fatima’s regular workplace and at a private restaurant unaffiliated with her employer, it occurred in a work-related context, the company-sponsored holiday party. Therefore, based on these facts, the harassment occurred in Fatima’s work environment for purposes of a Title VII sexual harassment claim.

https://www.eeoc.gov/laws/guidance/enforcement-guidance-harassment-workplace#_Toc164808037