TTSWYF,
Even if Jews understood Jesus was claiming divinity at Jn 8:58, it does not mean they were right for doing so. At Jn 5:18, Jesus was misunderstood by Jews as well, claiming that he was breaking the Sabbath and that by calling God his own Father, was making himself equal to God. Now, the question is, Was Jesus actually breaking the Sabbath? I don't think so? Do you?
Notice, the other accusation Jews brought up: By calling God his own Father, they concluded Jesus was making himself equal to God. Was he? He defended himself not by saying, "You are right, I broke the Sabbath, and I am making myself equal to God." No! Jesus instead tells them that "The Son is not able to do anything of himself...that all may honour the Son according as they honour the Father; he who is not honouring the Son, doth not honour the Father who sent him." (5:19,23, Young'sLT) Verse 30 says that: "I am not able of myseff to do anything...because I seek not my own will, but the will of the Father who sent me." Later in the chapter, Jesus told them that they were not seeking the glory of the only God (or, God alone) as he himself was doing. (44) Also, they had not heard his voice, or seen his figure or appearance. (V. 37) So, it seems Jesus was not confirming their erroneous take of him, rather, he corrected them by saying in so many words that he was different than the Father, and logically, that he was not making himself equal to God. What is your take?
At John ch. 10:30 onward, Jews again misunderstood Jesus' statement that 'he and the Father were one thing." Then, they wanted to stone him for blasphemy, because he was making himself "god" (or, a God, without the definite article in Greek). Were Jews correct in interpreting Jesus statements that he was claiming full divinity or equality with God? No! He defended himself by saying 'that if men of old were called gods, and the Word of God came against them,' why would they want to stone him when he was just claimingto be NOT God, but God's Son? (Jn 10:33-36)
At Jn 8:58, many trinitarians do not see Jesus claiming divinity. Many do, but not all. Actually, some trinitarians argue that those who believe Jesus was claiming divinity by using ego eimi are wrong. Here is a sample:
Seventh Day Adventist (Trinitarian): "I existed before Abraham was even born" (The Clear Word)
Evangelical Protestant: "I was alive before Abraham was born" (The NT in Plain English)
Catholic: "Before Abraham existed, I was existing" (Sao Paulo, Catholic Center)
Evangelical Protestant: "Before Abraham was born, I have been" (NASB, 1971, Alternate reading)
Jehovah Witness: "I came into being before Abraham" (21st Century NT)
Evangelical Protestant: "I have existed before Abraham was born" (Moffatt NT)
Jewish: "I existed before Abraham was born" (H. Schonfield)
Modern Israel: "Before Abraham was, I have been" (N.H. Snaith)
Syriac, 4th or 5th Century: "before Abraham was, I have been" (Agnes Smith)