Whom does the verse discuss?
Radak: It discusses heretics, who recognize and deny [Hashem].
Orchos Tzadikim (Sha'ar ha'Sinah DH Yesh Sin'ah): A Rasha who does not accept rebuke, it is a Mitzvah to hate him.
Malbim: Those who rise to deny Your Divinity and act to anger [You].
Why does it say "uvi'Skomemecha Eskotat"?
Radak: This is like "Mesan'echa Esna." The matter is repeated in different words, like is common. "Uvi'Skomemecha" is a To'ar (kind of person), with an extra Sav. It means Your haters, like "mi'Miskomemim bi'Yminecha" (17:7). "Eskotat" is quarreling, like Ketatah in Chazal's words.
Mesilas Yesharim (Perek 19): Kin'ah is when a person is zealous for Hashem's Kadosh name. He hates His haters, and tries to humble them as much as he can, so Hashem's Avodah will be done and His honor will increase.
Malbim: A sign of a lover is that he hates haters of his beloved, as if they hate him.
