I would expect that too, especially at some point when he was alone with his disciples teaching them. Since he (and the apostles) never point blank reveal this about God--and how could they not in light of how important monotheism was to Judaism?--I too feel I must reject it.
But, I would also expect him to have taught his disciples plainly to the effect, "I have distinguished myself from the Father in public and have called myself the Son and have described my relationship with him as one of mutual love and of him teaching me things to say and showing me what to do, and I have said the Father is greater than I, and in every way have made it seem like I was not the Father, but do not be misled: I'm just the Father in a different mode. As the Son, I'm in a different human mode of being in contrast to my omnipresent Spirit mode of being. That's why I speak this way as if I'm distinguished from the Father, because these modes of being are distinguished." I would expect it all the more since this concept is hard to grasp and not obvious and so obviously open to misunderstanding. It seems to me that, because the Father-Son relationship is not explicitly explained, speculation has filled the void.
I came across this verse in
John 16: 25 “I have said these things to you in figures of speech. The hour is coming when I will no longer speak to you in figures of speech but will tell you plainly about the Father."
So this sounds promising. He is going to speak plainly in order to teach them about the Father, so we can apparently take what he says at face value. Does he just plainly tell them he's the Father? No.
26 In that day you will ask in my name, and I do not say to you that I will ask the Father on your behalf; 27 for the Father himself loves you, because you have loved me and have believed that I came from God.
28 I came from the Father and have come into the world, and now I am leaving the world and going to the Father.”
When he said this, a light went off in their heads.
29 His disciples said, “Ah, now you are speaking plainly and not using figurative speech! 30 Now we know that you know all things and do not need anyone to question you; this is why we believe that you came from God.” 31 Jesus answered them, “Do you now believe? 32 Behold, the hour is coming, indeed it has come, when you will be scattered, each to his own home, and will leave me alone. Yet I am not alone, for the Father is with me."
So in his plain teaching, Jesus tells them that they can pray directly to the Father and shouldn't seek to have Jesus ask the Father on their behalf. He notes that they believed He came from the Father. Then he sums up the history of his ministry: He came from the Father and came into the world, and once he completes his ministry, he will go to the Father. And he finishes by saying that he's never alone--even when the disciples will forsake him--because the Father is always with him.
I can't read this "plain" account and conclude, "Oh, he clearly means he's the Father in a different form or mode." Taking the language at face value, he is not simply the Father. At any rate, I can understand why millions have read passages like this and concluded that Jesus is not the Father.