Moses said, I did it then, while I was of those astray

Question 41: In the answer to a previous question, you said that Moses did not apologize for his killing of the Coptic because he was a work of Satan. Rather, you said that he intended to kill the Coptic and it was a righteous act; so if it was right for Moses to kill the Coptic, then what is the meaning of his saying in Surat ash-Shuaraa, (([Moses] said, “I did it then, while I was of those astray.))?