This is really a non-news and the reason is simple, from a marketing standpoint you never want to mention the competitor's brand because it promotes that brand

This is really a non-news and the reason is simple, from a marketing standpoint you never want to mention the competitor's brand because it promotes that brand also, especially if that brand belongs to a newcomer/non-market-leader and you're the market leader. For example, if Coke ad (as someone else also reported) mentioned Pepsi, then not only is a consumer seeing "Coke" but is also seeing "Pepsi". The only time you see the competitor brand mentioned is when the ads are very specifically negative or when they come from an underdog against a market leader. The usual examples are Verizon-AT&T, Apple-MS, etc. Here the underdog or newcomer has nothing to lose so they will mention the market leader's brand. So, here MS is not afraid, rather it doesn't make sense for them to mention Linux or rather any *nix by name. But, if it was reverse, it totally makes sense for Red Hat to mention MS Windows by name.