Jruss, let us be careful use a little discernment, keeping the Golden Rule in mind. In the 'verse' quoted we see obvious double-standard, that sub-standard meat can be sold to a foreigner (non-jew). This is bad trade practice. I had posted earlier that the hebrews canNot be trusted to retain/ guard the authentic scripture = This is the reason.
Similar trickery is used in the verse on U$ury, where they can charge from non-jews, = racism ? fake superiority complex.
EDIT: in Deut 13 there is no verse 21. pls check, thanks.
Ticks, Trick$ & Traps - http://www.usDebtClock.org/
Hitmen Confess - https://www.youtube.com/watch%3Fv%3Dn7Fzm1hEiDQ
Misinformed finds - https://www.youtube.com/watch?v=HpROEzHEtOI