SB-To be the Son of God is to be of the same nature as God. The Son of God is “of God.” The claim to be of the same nature as God—to in fact be God—was blasphemy to the Jewish leaders; therefore, they demanded Jesus’ death, in keeping with Leviticus 24:15. Hebrews 1:3 expresses this very clearly, “The Son is the radiance of God’s glory and the exact representation of His being.” What is it about Jesus being God that bothered so many people then as it does now?
It's possible that the word 'God' conveys someone that is ultimate and above all else. For that title to belong to three separate persons seems to change the meaning of the word God at first.
The Bible clearly describes the Father (God the Father) as having attributes that God the Son doesn't have, because they are two separate beings although both retaining the title of God.
While Thomas acknowledged Jesus as being God, he didn't imply that the Son was the same person as the Father. I believe that it is saying the Son is the same person as the Father that may 'upset' people today.