A sentence towards the bottom of Sanhedrin page 5b speaks of kneading dough in a state of impurity.
דתניא פעם אחת הלך רבי למקום אחד וראה בני אדם שמגבלין עיסותיהם בטומאה ...
In the English Koren edition, Rabbi Steinsaltz translates this as meaning the people were impure.
As it is taught in a baraita: Rabbi Yehuda HaNasi once went to a certain place, and he saw people there kneading dough while they were in a state of ritual impurity ...
This reflects the Hebrew Steinstalz edition:
דתניא [שכן שנינו בברייתא]: פעם אחת הלך רבי למקום אחד, וראה בני אדם שמגבלין (לשים) עיסותיהם בטומאה, שלא היו מקפידים בטהרת עצמם בשעת לישה ...
Rashi, by contrast, interprets this passage as saying that the vessels the people used were impure:
בטומאה - לא הוו מקפידין לטהר כליהם:
In a state of ritual impurity - They weren't careful to purify their vessels.
(Mi Yodeya community translation)
The Schottenstein Edition reflects Rashi's interpretation. Why might Rabbi Steinsaltz have interpreted this ambiguous sentence in a way contradictory to Rashi (who is the most influential commentator)? Are there any Rishonim who support his interpretation?