The reply may be given from two angles:

First: the ḥadīth is weak. Al-Ṭabarānī recorded it in al-Muʿjam al-Kabīr (1/81/2): “Muḥammad ibn Isḥāq ibn Rāhūyah told us, saying: my father told us, saying: ʿĪsā ibn Yūnus told us, saying: my father told me from his father, from Umayyah”—with the same wording.

He also said: “ʿAbd Allāh ibn Muḥammad ibn ʿAbd al-ʿAzīz al-Baghawī, from ʿUbayd Allāh ibn ʿUmar al-Qawārīrī, told us; Yaḥyā ibn Saʿīd told us from Sufyān, from Abū Isḥāq, from Umayyah ibn Khālid”—with the same report.

Then he transmitted it through the route of Qays ibn al-Rabīʿ, from Abū Isḥāq, from al-Muhallab ibn Abī Ṣufrah, from Umayyah ibn Khālid, in a marfūʿ form with the wording: “…he would seek an opening and victory through the poor among the Muslims.”

I say: the entire chain hinges on this Umayyah, yet his status as a Companion is unproven; the report is therefore mursal and weak. Ibn ʿAbd al-Barr said in al-Istīʿāb (1/38): “In my judgment his Companionship is not established, and the report is mursal.” Al-Ḥāfiẓ said in al-Iṣābah (1/133): “He possesses neither verified Companionship nor any reliable narration.”

I add: the report suffers from another flaw as well—the confusion (ikhti­lāt) of Abū Isḥāq and his habit of narrating by saying ʿan (“from”) without explicit hearing, for he was a mudallis. Although Sufyān heard from him before his confusion set in, the remaining defect of ʿanʿanah is still present.

These points establish the weakness of the ḥadīth beyond doubt, so it cannot serve as evidence. This constitutes the first answer.