I agree, the narrative supports Ichigo holding back from them because he doesn't trust them.
He repeatedly pushes them away or fakes confidence in front of them rather than have any real moment of vulnerability or connection, and most important to the Ikumi moment is that the TYBW situation comes on the heels of TLA where, when he was the most vulnerable and in need of support in the entire series mentally, emotionally and in-battle, these two actively, literally fought against him - ignoring his pleads for them to listen to him the whole time.
Chapter 546 is titled "Hear Me", and the whole point of it is that he is trying to get Inoue and Chad to listen to him that Tsukishima is a bad guy, but they won't. Not for a moment. They don't trust him enough to listen to or believe him at all, not even to listen and consider his words. They simply reject him and chastise him and turn their weapons against him on Tsukishima's word.
Ichigo has had hard proof that in a he-said-I said situation they will not only not take his side, they won't even listen to it.
Just look at Ichigo's face, read his words, and then look at how Inoue and Chad respond to his vulnerability and attempts to reach out.
Inoue shuts Ichigo down over and over with this look like "I knew it. I knew you were like this deep down and I hoped you'd be better, but you're not", the distrust and dislike and suspicion she had as soon as his hollow power appeared flaring full-force with Tsukishima making her remember meeting him first and so being the one she had a crush on:
Chad is the opposite. Just shouting and glaring and blaming Ichigo for everything while he lectures with proverbial cotton wool in his ears, deaf to everything Ichigo has to say. He's patronizing, demanding over and over why Ichigo won't see things from his pov, but not once giving Ichigo space to say his side:
Again: just LOOK at Ichigo's FACE:
No amount of "I knew Tsukishima first" or "Tsukishima is also my friend" excuses the sheer coldness and refusal to offer sympathy the two of them show toward Ichigo here. Of course he wouldn't ever want to get close to that position with them ever again.
They are not safe to be hurt and vulnerable around.
On the other hand, after dealing with them Ichigo is now wary and trying not to be hurt by betrayal and rejection when Ishida shows up in 548 his expression is closing off:
Which is an expression much closer to the look he gets from here on out whenever anything is going wrong if Chad and/or Inoue are there.
Also, I don't recall Ichigo expressing thanks, gratitude or appreciation for either of them no matter what they do or do for him for the entire rest of the manga.
The closest for Chad is chapter 661 when Ichigo gives this wordless look and then turns away when Chad elects to stay behind to handle the statues Yhwach sent to whittle away the group Ichigo was approaching with:
And Ichigo acknowledging Inoue is the only one with him and therefore the one he'll have to rely on in 672, though he never follows through and actually relies on her:
So I think it can be argued that, at the latest, after TLA Ichigo permanently closed off parts of himself from these two.
