פירוש על עבודה זרה 114:4

The baraita implies that if the slaves had been circumcised and immersed they immediately stop rendering wine yayin nesekh. They do not need to wait until idolatry is banished from their lips, as R. Nahman stated.

Rav Nachman says that the baraita refers only to the children of female slaves. Slaves owned by a Jew are considered Jewish, and therefore these slaves do not make yayin nesekh. But the touch of slaves bought from non-Jews does make yayin nesekh even after they are circumcised and immersed, until they idolatry is banished from their lips.

The problem is that the baraita seemed to say that slaves bought from non-Jews and children of female slaves from Jewish households are treated the same.
Rav Nachman answers that they are treated the same when it comes to the impurity of their spit and place of treading. But they are not treated the same when it comes to touching wine.
But there is still a problem. If the spit and place of treading of slaves bought from non-Jews is impure, it makes sense to say that the same is true for the children of female slaves. But if the spit and place of treading of slaves bought from non-Jews is pure, then all the more so the spit and place of treading of children of maidservants born in a Jewish home is pure. And thus, according to the one who says that they are pure, the comparison must be that in neither case do they make yayin nesekh.

This is the mirror image of what we saw in section three. The comparison in the baraita is not meant to teach that slaves stop making yayin nesekh immediately after they are circumcised and immersed. Rather, it teaches the slaves bought from non-Jews are like slaves born into Jewish homes. In both cases, both adults and minors make yayin nesekh until they are circumcised and have immersed. This rejects Rav’s statement from earlier on this daf.
You will note that this section is the mirror image of the passage above that appeared in sections 2-3.

Rava allows the wine to be sold to Gentiles because the idolater who touched it clearly did not have the intent to drink or libate. He just wanted to see that it was wine. Note that even Rava, who is relatively lenient, does not allow Jews to drink the wine. As we have seen, once the non-Jew touches the wine, the Jew may not drink it.

Other rabbis rule more strictly, prohibiting a Jew from even selling the wine. We have an interesting description of people going out to the street and announcing the rulings of the respective rabbis. It sounds like this issue was one of great practical significance to the Jews of Babylonia.