Rashi citing Megilah 12b: The seventh day was Shabbos, when Yisrael eat and drink and begin with Divrei Torah ¹ and praises, whereas idolaters eat and drink and begin with obscenities. Refer to 2:1:2:1.

Vilna Gaon: The men heard their wives at Vashti's party, and began taking about their wives. They argued about whether Parsiyos or Madiyos are prettier; Achashverosh said, my wife is Bavli - do not you want to see her! They said yes - naked ¹ . (Megilah 12b)

Malbim: This was to prove that he married her only for beauty, and not because she inherited the kingship. He is king due to conquest! He showed this in five ways. (a) He called her via Sarisim, and not via all the royal officers. (b) He did not call her via her Sarisim, rather, via his, as if she is a concubine. (c) He said "Lehavi" (11), i.e. Bal Korchah (against her will), like a Shifchah. Also refer to 1:11:1:1, 1:11:2:1.