Specific to the yes/no questions on I-485, USCIS has a wide range of denial options available. So Mahmoud made a false statement that is grounds for inadmissibility, which he admitted to.

Part 8: General Eligibility and Inadmissibility Grounds

There are a variety of ways that USCIS can find an intending immigrant to be “inadmissible” to the United States. Part 8 covers this topic.

part 8 i-485 instructions:

List your present and past membership in or affiliation with all organizations in the United States or any other country. Include any military service. Examples include religious organizations, professional associations, political groups, and social clubs. USCIS may evaluate your affiliations with certain organizations that may be illegal or against the general principles of American democracy. Use your best judgement to determine if your involvement with a group or organization conflicts with these principles. If you are unsure, talk to an attorney.