Officers said the comments are suspected of inciting hatred against the government or raising discontent among the people.
The police declined to give more details regarding the comments allegedly made, adding that more arrests could be made.
The 26-year-old was granted bail after his appearance at the West Kowloon Court, and his case has been adjourned to January 14 next year.
Senior inspector Lam Yuen-yee was killed in an anti-smuggling operation at sea in September. She was buried with full honours earlier this month.
Last updated: 2021-11-12 HKT 20:09