We can suggest the following explanation:
The command to “compel all the inhabitants of the world...” applies only in situations where fulfilling the command does not cause the Jew any personal harm — such as financial loss, loss of potential profit, and the like.
Since the laws in Shulchan Aruch cited in the previous section deal with matters of commerce and sale, as well as lending and borrowing, they address situations in which a person either derives benefit from the transaction — immediately or in the future — or acts out of the interests of maintaining peaceful relations with the non-Jews (mipnei darchei shalom), and the like (including the desire to establish the reciprocal benefit that precludes the prohibition of lo techanem).
In such cases, it is permitted to sell to them.
By contrast, the prohibitions of “You must not cause it to be heard” and “placing a stumbling block” (lifnei iver) are negative commandments. One may not violate them even in a situation involving financial loss — and certainly not merely to avoid a missed profit.
Accordingly, regarding our current discussion: In such a time and place (e.g., in this country) where the Jewish effort to influence the nations to accept the Seven Laws involves no danger whatsoever, nor any financial loss or loss of potential profit — and on the contrary, such efforts only bring assistance and benefit to the Jewish people (as will be explained below) — the obligation to “compel all the inhabitants of the world to accept the commandments given to the descendants of Noach” applies in its full force.
