How were the polytheists called "Abd al-Rahman" despite their rejection and objection to the name Al-Rahman, as happened with Suhail ibn Amr during the Treaty of Hudaybiyyah?

Scholars have differed concerning the name of Allah, "Ar-Rahman." Most of them have concluded that it is an Arabic name derived from rahmah (mercy), and not as some have claimed, that the Arabs did not know it. They supported this with pre-Islamic poetry and the existence of names like "Abd Al-Rahman" before Islam. As for the polytheists' statement: (And what is Ar-Rahman?), it has been answered that it was a question about an attribute, not an essence, or that it was a denial and falsehood despite their knowledge of it, or stubbornness and arrogance on their part. Al-Mu'allimi Al-Yamani believes that their arrogance was a form of mischief and sophistry, and that they knew the name but feigned ignorance of it. Perhaps their objection was to the Basmala (Bismillah), which contradicted what they were accustomed to.