Magazines are there to make money, not to actually review bikes, that's just their product and appese the advertisers.
They review the bikes and call real entry level (i.e. decent enought to be a lasting worthwhile bike used for more than trundling down dome roads and trails) 'Mid-Range' because people like to think they have a 'mid-range' bike and call it something better than it is.
They called entry level bikes, entry level bikes, because they were the cheapest MTBs that would actually work well, off-road, and not fall to bits. The kit on them may not have lasted as well as better spec'd bikes, but they were competent off road. Any reviews or group tests I ever saw on entry level bikes, all seemed fair comment - sure hardly aspirational stuff, but bikes perfectly adequate for newbies to start hitting the trails.
Mid-range bikes were grouped, tested and reviewed as such, because the magazines had a good handle on what people bought, largely, as mid-range bikes - I'd hazard a guess in a very similar way that car magazines handle group tests of cars that are considered mid-range (same as they have other categories, like executive).
When magazines review bikes, together, they do so on the basis that they have a rough idea of what people are considering for the category stated. Their intent isn't focused on making people feel good, it's in providing articles that would make people want to read, and keep reading their magazine.
It makes you feel good and the magazine know that, so do manufaturers and retailers, look at Halford or ToyRUs for examples, they know average Joe knows nothing.
The target audience for MTB mags is nothing
like your "average Joe" nor the person who buys bikes at toy shops or supermarkets.
Mags reviewing bikes isn't about making people feel good - it's about providing reviews on things that are actually popular, and people actually buy in numbers, that will help their circulation. It's about appealling to their audience, and your "average Joe" or supermarket buying BSO owner, isn't the likely target audience (nor for that matter buyer) of MTB mags.