There's nothing about this that stops you from having multiple identities. You can generate a unique key for a project or github account, and then only using that key for that purpose. This allows trust that "MarvinTheMartian" the maintainer of the "Q-36 Space Modulator" doesn't have false commits under their name (maybe important for their reputation!), while still giving the plausible deniability that "therealmarv" isn't developing cartoonish WMDs.