וטעם שאסור ללמוד תורה לגוי הוא מפני הערלה שבו ויש בו סוד שלא להכניס הטומאה בהיכל הקדש
And the reason it is forbidden to teach Torah to a non-Jew is that he has a foreskin. And there is a secret [mystical idea?] so as not to allow impurity into the holy sanctuary.
Have any poskim applied this in practice to justify teaching Torah to non-Jews if they are circumcised?
If yes to the above, given that many non-Jews nowadays are circumcised, can you teach Torah to any non-Jew (if you don't know that they are not circumcised)?