Geez people. This isn't news! Microsoft was always more than a gaming company. Gaming was never its core. Microsoft used to be synonymous with Windows, and Windows was synonymous with "PC operating system", and quite honestly, I miss those days, back when Windows was so ridiculously good compared to everything else on the market, that nothing else was worth a second thought. It's not an insult to Xbox to say that it isn't Microsoft's core. It's an insult to Microsoft to say that Xbox is Microsoft's core. They're not saying they aren't associated with it, they're just saying that Microsoft is a fucking ENORMOUS company and that Xbox doesn't even BEGIN to cover what Microsoft is about.
Gaming is the core of Nintendo. Gaming is NOT the core of Sony, and NOT the core of Microsoft. However, gaming IS the core of Xbox, and IS the core of Playstation. All companies are trying to do with statements like this is to get consumers to understand that the company is bigger than gaming, and it's the gaming brand that is about gaming, not the company as a whole. Nintendo is the company that has to justify expansions into markets like wellness and health with "we're still a gaming company at our core", while Sony and Microsoft have no such need, and shouldn't be criticized for trying to distinguish their gaming brands from their company as a whole.