And all this means what, exactly? The actual left is way more versed in coalition building and working with people who don't share their views than the right. Give me one example of coalition building on the right, or where the right have ceded ground on anything? I think these ideas about aggression and disagreements are overblown, because really, the issue of leftist politics is the solidarity that once existed has been dismantled by the right and its attacks on unions etc. And its a problem that white folk expect minorities to take positions that go against their interests for the sake of the common good - see Keir Starmer. Also, the problem is that both-sides-ing this whole debate is never going to work - its never going to make lasting social justice changes.
And if you think that the divisions in this country haven't always existed in some form, and that they are easy to heal, I think you're wrong.