I know you've already received an answer from your account executive, but I'll explain why we do what we do.
Once you install DevForce, the DevForce OM Designer Extension is installed and enabled within Visual Studio. It's this extension that adds DevForce-specific attributes to your EDMX and controls code generation. We made the decision that when the extension is enabled, any EDMXes you create, in any type of project, will by default be "DevForce-enabled" EDMXes. You can turn this off on an EDMX by EDMX basis by setting the "DevForce Enabled" attribute in the EDMX to false, or you can disable the designer extension, which turns off DevForce-enabling of all EDMXes.
We haven't previously considered disabling DevForce by default except for "DevForce projects". Although you can use the templates to create a DevForce project, we don't require this: so any type of project can be a DevForce one by including the appropriate assembly references. This is an interesting request, though, but we'd like to hear from others that this is the desired behavior, since we can also imagine users being quite irritated with the opposite behavior too.
Thanks for your feedback!