Is it also “open source” to reproduce nontrivial parts of code verbatim, violating attribution and copyleft? Because that’s what’s going on with Copilot. Would the pro-GitHub section of the OSM community also be okay with the same being done for OSM data? 
Anyone claiming to be in favor of open source or copyleft and still using GitHub is utterly hypocritical. The amount of support this nonsensical thought process is receiving is nothing short of disgusting.