Yeah, but there are a litany of explanations that could account for that lack of success, and the fivethirtyeight offering of "votes are won by statistically appealing to the greatest number of this mostly static lumbering mass" is but one of them. Ask a Bernie voter and they'll give you a million examples of media bias and the DNC using their weight to undermine his chances of winning. These are, at the minimum, confounding variables that need to be addressed, but fivethirtyeight doesn't address them; that's not their thing and that's fine, but it makes them limited.
The goal of the article was to take strategies laid out by the campaign (that were built on supposed lessons from 2016) and see if they held up. The conclusion is they didn't work, which doesn't require any kind of reasoning, and the content examines potential factors for why they didn't work with pretty solid reasoning.
If your criticism boils down to the fact it doesn't include your preferred reasons for why he lost, is it fair to maybe ask that if there exists plenty of factors to explain the loss outside your preferred set, are those you like actually true or even necessary?