What's your point? The thread author says that he doesn't know. I'm not taking a position. But I am tired of simple positions on complex issues with conflicting data.
Of course it's not binary. But we do have clear, incontrovertible evidence of how this disease behaves when unleashed without any sort of actions taken. So in terms of using this "unknown" as rationale for why "we shouldn't be worried" is demonstrably silly (through recent past experience).
As far as developing future treatments and understanding the immune system's response to this disease, it's absolutely important to understand the cross immunity and how T-cells are involved in the immune response. There are a lot of unanswered questions!
My point is: I think people take this T-cell cross-immunity to mean at least one of several things (none of which are true, and all of which are damaging in terms of controlling this disease and bringing infections to zero in the US) 1) The herd immunity threshold might be quite low 2) Asymptomatic transmission is not a thing because asymptomatic people are effectively fighting the virus with their T-cell cross-immunity 3) Severity of the illness is likely to be low if you have T-cell cross-immunity, so that's some sort of golden ticket if we can identify those people who have that. 4) Actually tons of people have already been infected and don't have antibodies as a result of T-cell response, so this disease is no big deal (this is probably the most damaging naive hot take).
Agreed that it is that binary thinking at work that is hurting us, for sure, here. Unknowns like this mean 1) We must redouble our efforts to eliminate a disease that endangers our hospital systems and 2) We need to continue to research what results in mild responses to the virus and what leads to poor outcomes, in the hopes of finding better treatments.
Viral load in samples gathered from individuals varies by 9 orders of magnitude. That alone shows how non-binary the immune response to this virus can be, and explains the dramatic differences in how efficiently people spread the disease.
You were the one who posted the Medium article saying the virus is gone now in Switzerland (it's not gone)...so forgive me if I thought you might be overly credulous when it came to the positive implications of T-cell cross immunity.
