The article is a detailed piece of investigative journalism regarding the use of analytical models and social media to influence democratic elections by unelected super rich individuals. It is not a debate on whether either the leave or remain side were right, but that elections, especially tight ones where marginal swings can be critical, are being manipulated by wealthy self interested parties. Had you read the article you would know this, rather than simply assuming the articles content and position. Sorry to quote the Observer, but unfortunately the Mail is too concerned blaming benefit scroungers for Kim Kardashian's arse or something, whilst the Observer actually has some genuine journalists left.
Also, whilst I really don't want to go there, the people voting against the Government is technically correct, even though the leave campaign was actively backed and lead by key members of said govt, but the media being pro EU is a pretty difficult position to justify.