It is ineffectual at helping the cause. If someone sees him sit, they don’t consider the legitimacy of why or make any appreciable change on his behalf. They argue about whether he should be allowed to sit, effectively bringing attention to only himself and not why he sat.

So people should ignore him and make his decision ineffective at drawing attention. Then, he either can keep sitting but no one knows so no one cares; do something that actually helps the cause; or quit bothering altogether. Albeit given that two of those options would have the same effect since no one is paying attention to him.