Google's longstanding tension with antitrust regulators is perhaps more pronounced in the European Union than anywhere else. EU Commissioner for Competition Margrethe Vestager has put Google under a microscope in many ways, and one of the bigger cases against them that she's pursuing is concerning the Android OS. Antitrust authorities have argued that Google's handling of Android is anti-competitive. Their arguments mostly center around giving manufacturers and users choice in the applications installed on their phones, and accusations of anti-competitive bundling concerning the Play Store and the apps that manufacturers have to preload on a device if they want the ubiquitous app market on board. Google took to their blog to point out the ways that Android and their handling of its distribution not only fails to discourage competition, but actively encourages it.
According to Google, one of the core tenets of the case against Android that the EU is bringing is that it does not compete directly with closed ecosystems like iOS. Google refuted this in their blog post, and brought up a list of reasons that, in the view of competing with other ecosystems, their handling of Android is anything but anti-competitive. One argument that they presented is the fact that no OEM is required to preload the Play Store and the associated Google apps. While an OEM wishing to have the Play Store on their device does have to include certain Google Apps in order for Google to "sustain" their investments and efforts in their products, OEMs are free to include an alternate app store, or have the Play Store and Google Apps with competing products preloaded on their device alongside Google's services.
Google also touched on the subject of fragmentation and device compatibility guidelines, which enable the vast app ecosystem that Android enjoys, as well as a consistent Android user experience. They noted that the entire affair is completely voluntary, though it could be argue that devices that don't follow these guidelines can't compete in a market laden with devices that do. Google's point with this particular argument, and indeed the salient theme throughout the post, is that the choice is in the hands of the manufacturers and users, and Google exerts only a bare minimum of control.