Simple categories matching contentious:

• matter,
• item,
• subject,
• topic,
• issue,

Members with property contentious:

• culture,
• land_right,
• politics,
• tenure,
• religion,
• financial_issue,
• territory,
• animal_right,
• division,
• role,
• immigration_policy,
• extraneous_matter,
• copyright,
• online_copyright,
• right,
• autonomous_territory,
• publication_right,
• property_division,
• child,
• social_policy,
• sport,
• market_access,
• gun-control_laws,
• ethics,
• history,
• intellectual-property_right,
• trade_rule,
• faith,
• competition_policy,
• race_religion,
• textile,
• type,
• abortion_laws,
• discrimination_claim,