I don't really know how to reply, I offered a productive discussion but you seem to refuse it.
Since I obviously disagree what is "left" (and since I identify on the left, I would dare to say I have a better idea what it actually is), clearly I don't understand who you mean by "we" and "them". (Which is funny especially since you accuse the left from seeing things in binary.)
See, I offer to educate you, what actually left is about, maybe you would find that you actually agree with it (which wouldn't be surprising for me). But unless you give me an example of person you think is leftist and has those opinions, I cannot proceed - I don't know what exactly is your misconception about left.
Your remark about Brexit is funny - I do consider Jeremy Corbyn to be leftist, even though I disagree with him on Brexit. So does he call himself racist?
Give me a specific example (aka quote), then we can discuss if the statement or the person is leftist and how much.
The left is actually pretty wide, diverse set of people, with many opinions (that's why I asked what the "narrative" means in this context, there is no one). You certainly cannot categorize it as "them" and "us". (And you are the one giving blank statements like "the left are utterly incapable of doing".)
About the experts - it's not really about the profession either. I mean, if you were given the choice to trust the same expert person, 1-year into their career versus 20-years into their career, you would probably choose the latter one, who is probably the bigger expert of the two.
I think the key thing with "experts" is actually not whether to trust experts or not, that's a false dichotomy. The real issue is: How to choose an expert? Which is tricky (although I know some tricks), but beyond my interest in this discussion.