Keep in mind that of US journalists 50% ID as (lowrcase) independent, but 28% as Dems and only 7% as Repubs. So there is inherent bias on one side, if looking at affiliation.
Also, if journalists are reluctant to be identified as Republican, perhaps the Republican party should do some soul searching about why this is so.
Assuming there’s no bias is naive.
Note that I'm not taking a position on those implications, but am saying according to your logic the above is sound.
Also according to your logic Dems should do soul searching because lumberjacks and truck drivers are mostly Republicans...