Re: I give SuperMicro the benefit of the doubt.
"Not clear they can sue unless they can prove some sort of conspiracy."
Sure they can. I think you mean that it's not clear they'd win the lawsuit. That may (or may not) be -- but if the Bloomberg story actually made false claims without having a reasonable belief that they were true, then Bloomberg would lose.
But suing them would bring a critically important benefit even if they lost the lawsuit: it would force Bloomberg to come forward with their evidence, which would at least give everyone something more than hot air to go by.