I didn't think of the fact they may need to cast an "American" or whatever, and just take whomever is available, even if they are German or Romanian or whatever. I should have specified "northern European" or "UK", instead of just "European".
In Shanghai, I shared a hostel room with a Polish man and a local Chinese man, both had better English than I do, an average American white guy.
Also, not attempting to enrage anyone, nor being racist, just that the dialogue from a character that is supposed to be from the US or UK should sound much better than William Shatner.
[only if this is about C-Dramas] Dubbing everything in C-Dramas is common. I've watched C-Dramas where even the foreigner was obviously dubbed.
I watch all in the original audio, if anything is dubbed, I haven't noticed.