good.
FPI's Strength of Record (which has BYU #3) has 7 SEC teams in the top 20 (the top 6 you listed plus Oklahoma). I'd agree with Mizzou and Ole Miss probably not deserving a top 25 ranking at this point, but those 2 along with Arkansas are 26-28 in SOR so that's not too far out.
So yes, there is likely a bit of bias, but much of that has been earned over the years through strong play in bowl games, playoffs, etc.