According to Rabbi Ovadiah Yosef the prohibition for non Jews to learn Torah outside from the Noachide laws extends to even also Jews responding to questions on Judaism in general

So according to this rationale this sub reddit should not exist and is לא לפני because non Jews are able to access it and begin to engage Jews with questions on Torah/Judaism.

Heck even go one step further according to his ruling then all Jews should either move to Israel where they are the majority and have less chance of engaging with non Jews on religious Jewish matters or attempt to mass convert non Jews outside of Israel to get around the prohibition of teaching Torah to non Jews