Not that I want to make this into a competition of who shrieks and cries more, I've seen several times how game ideas for only OCs get reactions of "good riddance to IJ". So it is a big deal to some people.

However, I believe that on both sides the crying comes from a loud minority.

It feels like a hollow excuse to say that OCs are self-inserts or precious creations when players clearly choose their canon characters for same kinds of reasons. Why don't these players constantly shame the authors of their canons? Canon character is nothing more than a writer's OC.