Elliot is the kind of guy who always is concerned with others' dignity and agency. He also is the sort of guy who would be very easily embarrassed by seeing someone naked, human or synthetic. The nudity taboo is a real and powerful thing, you know!
I would rather have a moment of temporary embarrassment than the permanent horror of seeing someone taking a vegetable peeler to their own face.
What we need to remember about Roko as well is that her shifting to a chassis wasn't her choice. One moment she's just had a nice conversation with her friends, the next she's woken up and been told that her body has been crushed beyond repair, but hey that's okay, there's a shiny new chassis that covered by the other guy's insurance.
When an AI changes their chassis, they have a choice about it. It may take a while to get the settings right and as Beepatrice said, she didn't feel comfortable in her second chassis, but she felt much better in her third. But Roko never had that choice and in fact was told that her old model was now out of production, that's just pulling the rug out from under her again and again. She's never had the time to process what happened to her, to adapt and to make a decision for herself. Instead she was told "Here's chassis type A and here's type B. They're pretty much the same except B has a butt emblem", that's not a choice.
Just by comparison when someone loses a limb, they go through intensive psychological counselling to help them deal with the loss of the limb and to prepare them for the prosthetic they could end up getting. You have someone going from having a healthy limb, to a bloody and bandaged stump, to a healed end to where their limb used to be, to, depending on the model of the prosthetic which could be a claw to a lifelike but still fake replacement. That is a lot of mental trauma to work through and a lot of time to get to a place where healing can begin. And from what I can see, Roko didn't get that.
From what I've seen of the last major AI storylines (Bubbles' PTSD and Roko's dissociation), I believe Jeph is trying to say that although AI can be and are far more advanced than us in many way, their treatment of mental illness is almost medieval.