For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
By unbiblical that would mean what? Would you then say that interpreting scripture that holds symbolisms such as dragon, beasts, etc. is also unbiblical and that we should read it as is and not ask what these things represent? If Simon's carrying of the cross is insignificant, I don't think there would have been a need to mention it in scripture. It must have meant something that's why it was mentioned. Everything in the Bible is important. Everything in the Bible signifies something that man should know about. If you read further on you'll find two of Simon's sons are also mentioned in the Bible. That could have been why it was important to make mention of Simon's carrying of the cross.
In these few bible verses about Simon of Cyrene (Matthew, Mark and Luke), it is very clear that he was ordered to carry the cross of Jesus. Since the gospels record the actual events of that day, there are no symbolisms or ‘hidden messages’ to interpret. Mark’s gospel may have mentioned his sons names as a way of informing his readers at the time which Simon had to carry the cross for Jesus (Simon was a very popular name of the day and perhaps at the time, there would have been several Simon’s visiting Jerusalem from Cyrene for the Passover celebration).
Since the bible makes no other mention of Simon’s life, we would only be speculating on what sort of impact this event may have had on his life and to what degree.