Ghamidi Sahab Tafsir Surah Bayyinah
I think this is with reference to the kind of arguments one builds when they are determined to evade the message of truth. Because verse 4 onward answers this point, that when something direct was given to them in the form of pointers, even then they insisted on their perverseness. Also, this was not addressing all the People of the Book and the Idolaters, this was specific to the ones among them who had decided to not use their intellect and to deny the message of Prophet (sws) at all costs.