Russia is committing genocide in Ukraine, yet Musk thinks the best thing to do is to negotiate peace on Moscow's terms. He may have shown his support for Ukraine in the past, but statements like this only hurt the Ukrainian cause, which calls for the liberation of their entire sovereign nation. It's quite telling that the Kremlin reacted so positively to Musk's words.
It's a testament to the power of Western and Ukrainian propaganda that when someone suggests peace is the best outcome, they're mercilessly attacked by a mob of war-hungry Twitter "keyboard warriors." Most of those attacking Musk were undoubtedly pro-Ukrainian bot accounts with the sole purpose of subverting the discourse regarding the situation in Ukraine. Peace and compromise shouldn't be controversial.