Why does brutus say about killing Marc Antony?

Brutus argues against killing Marc Antony because he believes that doing so would be unnecessary and could be seen as a brutal act. He feels that Antony poses no threat as long as Caesar is dead, and that killing him would make them appear more like tyrants than liberators. Brutus emphasizes the need to maintain honor and justify their actions, suggesting that killing Antony could undermine their cause. Ultimately, he thinks sparing Antony would demonstrate their noble intentions.