The reason that the authors retracted the study was that they were basing their analysis on data that had been compiled by a company called Surgisphere, whose methods came under question. The authors became concerned when Surgisphere apparently was uncooperative in an attempt to audit the provided data, which is ultimately always going to lead to a retraction. Around the same time that this paper was retracted, the New England Journal of Medicine retracted another study that relied on data from Surgisphere, but it was unrelated to hydroxychloroquine. This is clearly a story about statistical reliability more than it is about hydroxychloroquine or anyone trying to attack Trump. One issue here is that the retraction is not the result of the data being shown to be inaccurate, just that the authors are no longer convinced that it is reliable, which are different things. It may be the case that the underlying data is bad, or it may be fine, but since they can't stand behind it, the paper no longer meets the standards that outlets like The Lancet and New England Journal of Medicine adhere to. I can find no concrete connections between Surgisphere and Bill Gates, nor between Gates and Surgisphere's owner, Sapan Desai, so unless Alex can substantiate that, I'm left to assume he's kind of just making it up.