We see this sometimes that an article gets upvoted when a similar article has already been posted. Yes posting first about a topic should carry some weight but there are other factors on these feeds such as amount of REP or REL staked which also carry weight and increase visibility of an article. On balance I don't like to just upvote another article because it was posted first, as these results in two articles on the same subject being in the Relevant feed which reduces the quality of the feed imo. Sometimes there are rare occasions that deserve a couple of articles in the Relevant section, but I don't think it's the case on this topic. Oh and don't assume it was me that upvoted it (I haven't) as there is plenty of other REP in this feed 😉