This verse explains why...

John 5:23 That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him.

And how is it you folks mention John 20:28 but ignore what John states in verse 31..."Son of God".

28 And Thomas answered and said to Him, "My Lord and my God!"

29 Jesus said to him, "Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed."

30 And truly Jesus did many other signs in the presence of His disciples, which are not written in this book;

31 but these are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in His name.