Windows 10 to lock out Linux with non-disableable Secure Boot

The slide is below and clearly shows that Secure Boot "must be enabled" when shipped and its then up to the OEM to decide "whether to allow [the] end user to turn off Secure Boot". This, in turn, could potentially lead to OEMs locking out Linux or at least making it very hard to install an alternative OS.
 
http://www.neowin.net/images/uploaded/2015/03/windows-10-secure-boot_story.jpg
 
Neowin has reached out to Microsoft to ask about the validity of the slide and whether Microsoft will give the final say to users or OEMs on whether they want to install an alternative operating system.
 
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