It is genuine, it's just one with which you don't agree.
Well, there's no maybe about it. It's definitely not fake (English is your first language, isn't it? My apologies if it isn't, I just always thought you were an American).
The question of what constitutes a "western" is as old as cinema itself, probably. Personally I think people fall into two trains of thought here: Those who insist that a western may only be a western if it meets a couple of fairly straightforward but inflexible geographical and historical criteria (set in the North American West, circa approx 1850-1915), such as our man @Phil_H for example, and those who think of the western more thematically and are more amenable to the concept of the western being displaced in space and/or time whilst still remaining a western, fundamentally. That's fine of course - I subscribe to that opinion myself - but then, once you're blurring those borders of where a western ceases to be a western any more, I think you have to accept that a million different people will likely posit a million differing criteria, all justifiable to at least some degree. This of course can become a real f*cking headache when compiling any sort of western-themed chart, list or other consensus. Is Star Wars a western, is Reservoir Dogs a western, is Seven Samurai a western etc. etc. So with that in mind, I feel some some manner of criteria needs to be adhered to when compiling many lists into one - and Phil's borderlines are really better than anyothers for this purpose since they're the least open to interpretation - but, for purely individual lists, people should be led by their own "feeling" on each film as to whether or not it's a western.