أَفَلَ يَرَوْنَ أَلاَّ يَرْجِعُ إِلَيْهِمْ قَوْلاً
...
Did they not see that it could not return them a word (for answer),
This is about the calf. `Do they not see that it does not respond to them when they ask it and when they speak to it!'
...
وَلاَ يَمْلِكُ لَهُمْ ضَرًّا وَلاَ نَفْعًا
and that it had no power either to harm them or to do them good!
Meaning in their worldly affairs and matters of the Hereafter.
Ibn Abbas said,
"Nay, by Allah, the moaning sound of the calf was nothing but wind that would enter into its behind and come out of its mouth, thus causing it to make a sound."
In a Hadith of Al-Fitun recorded from Al-Hasan Al-Basri, it is mentioned that;
this calf's name was Bahmut. In reference to the excuse of these ignorant people, they claimed that they were merely ridding themselves of the jewelry of the Copts. In the process of doing so, they cast the jewelry (into the pit of fire) and ended up worshipping the calf. Thus, they were seeking to rid themselves of something detestable, but wound up doing something even worse.
This is similar to an authentic narration reported from Abdullah bin Umar.
A man from Iraq asked him about the ruling of mosquitoes' blood if it get on one's garment.
The man wanted to know if it is permissible to pray in such a garment or not.
Ibn Umar replied by saying,
"Look at the people of Iraq. They killed the grandson of the Messenger of Allah, Al-Hussein, and yet they're asking about the blood of the mosquito."