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I was thinking something like, if you're on the blacklist, editing should be refused.
Literal
Blacklist [on-に] be-listed [if-ば] editing [object-を] refuse [something like-てなこと] was-thinking.
Casual spoken register with a small colloquial reduction. ~てなこと is a casual contraction of ~というようなこと ('something like X,' 'along the lines of X'), used to frame a vague or tentative thought. The て is a truncated という, and な comes from the copula/attributive link. Very colloquial, rarely written. Two notable grammar points in the quoted thought: ~ば conditional (載っていれば 'if it is listed') and the verb 載る ('to be published/listed') in its ~ている resultative form. 編集を拒否する is a casual wiki-era expression for 'refuse the edit.'