«أَفَمَنْ يَعْلَمُ أَنَّمَا أُنْزِلَ إِلَيْكَ مِنْ رَبِّكَ الْحَقُّ كَمَنْ هُوَ أَعْمَى»
Can one who knows that what is revealed from your Lord is the truth be like one who is blind?
The interrogative hamzah opens a comparison, and ka-man raises the question of likeness. Context makes it clear that the two states are not being equated; their distinction is being emphasized.
The interrogative force is rejection of equivalence. The presence of a comparison marker does not mean the speaker intends to affirm likeness.