Can you imagine how these lines, if records had been kept, would be 'venerated' or whatever by some today? By the grace of God we don't know their names and their history (if any great...great nieces/nephews of Jesus are alive). Obviously first century Christians knew that it was all about Jesus, the fact that some were 'mother/brother/sisters' meant nothing special to them - they needed a savior.
This is not what sacred scripture tells us. Jesus thought it was important enough to bind John and Mary as mother and son that this was the last of his actions from the cross before the following verses tell us all was now complete. That might not mean anything special to you, but undoubtedly these words from a nearly dead Jesus were incredibly moving to John and Mary. And anyone else in earshot. Do we not cherish the last words and wishes of our dying loved ones? [And as an aside, if there were other children, isn't it interesting that Jesus chose to have an apostle care for her, not one of his siblings? Jesus CHOSE to place her among those founding his church.]
Does anything in the New Testament negate the commandment to honor father and mother? It seems obvious that the apostles honored her to some extent as evidenced by her presence when the Holy Spirit descended upon them and by mention of this in scripture. We know John honored her as scripture tells us that he took her into his home. And in his Revelation he describes her appearance in heaven.
Furthermore Luke (chapter 1) draws parallels between Mary and the ark of the covenant (2 Sam 6). You can see some in this table.
Also early art in the catacombs (earliest typically dated about 120-150) depicts Mary. This tells us that by the end of Christianity's first century or at the beginning of its second, clearly some thought Mary was special, contrary to your assertion.