It is interesting to ponder what would happen if all the anit-kafir passages of the Koran were published in a book with the words "kafir, jew, christian etc" replaced with "Muslim" eg
His likeness is that of a DOG....That is the likeness of the Kafirs (Koran 7:176)
Let me give you the full version of that 7:176, so that people do not misunderstand with few clipped words Mr. DH..
007.176
YUSUFALI: If it had been Our will, We should have elevated him with Our signs; but he inclined to the earth, and followed his own vain desires. His similitude is that of a dog: if you attack him, he lolls out his tongue, or if you leave him alone, he (still) lolls out his tongue. That is the similitude of those who reject Our signs; So relate the story; perchance they may reflect.
PICKTHAL: And had We willed We could have raised him by their means, but he clung to the earth and followed his own lust. Therefor his likeness is as the likeness of a dog: if thou attackest him he panteth with his tongue out, and if thou leavest him he panteth with his tongue out. Such is the likeness of the people who deny Our revelations. Narrate unto them the history (of the men of old), that haply they may take thought.
SHAKIR: And if We had pleased, We would certainly have exalted him thereby; but he clung to the earth and followed his low desire, so his parable is as the parable of the dog; if you attack him he lolls out his tongue; and if you leave him alone he lolls out his tongue; this is the parable of the people who reject Our communications; therefore relate the narrative that they may reflect.
it is clear from that verse Muhammad and his followers hated those who questioned him., so they compare such person with "DOG" . Not only that verse there are many verses that spill hate on those who question Muhammad/Islam/Quran.
in other words., It is not a special verse for kafirs.