It means that the focus of our criticism should be against the right, rather than those on the left.
It is an encouragement for those on the left to put aside our disagreements about how we can reach the better future we are all fighting for, and instead fight those who want to silence and oppress us, and those who put the interests of the ruling class before the needs of the working class.
Does “don’t punch left” mean you can punch anyone slightly to your right?
If not, what if you paint everyone to your right as Nazis and Nazi sympathizers?
No, it means you centralise before you swing. That requires some empathy.
It means that the focus of our criticism should be against the right, rather than those on the left.
It is an encouragement for those on the left to put aside our disagreements about how we can reach the better future we are all fighting for, and instead fight those who want to silence and oppress us, and those who put the interests of the ruling class before the needs of the working class.