The all fascists should die thing is not productive at all. The goal should always be to get people to agree with you, not kill everyone who doesn't
And you can change people's mind. It's hard and a difficult process, but you need to do it and it's more productive than killing people because then they can help you change more people's minds who you otherwise couldn't reach
The war against capitalism will be won by filling the hearts and minds of the proletariat, not the mass graves with them.