Obviously they were horrified by things like Sid's tearing apart/mashing together/melting/etc. of toys, but that's not really a repaint, and in scenes like Woody's repair:

At 0:45, the riff implies he might be afraid, even if we can't see his reaction, but afterwards he ultimately appreciates the restoration, but again, that's not quite what the topic of discussion is.

In many doll customizing or repaint videos, the original hair and paint are simply stripped away and replaced. In more extreme ones, the dolls are disassembled and rebuilt. Even as I type this, I'm watching a video where the artist replaces the head and hands of one doll with those of two different dolls.

The toys in Sid's room are horrified and angered by what's been done to them and seek revenge, but Sid's purpose wasn't to remake them into something new, just to break them or make things to scare his little sister. They remember being whole, normal toys.

Woody being restored doesn't erase his memories of being played with and cared for by Andy, but the purpose was to bring him as close to his original state as possible.

In Toy Story 4, we kind of explore the creation of new toys and their personalities, but Forky wasn't created from old toy parts, he was a unique entity.

Would a repainted doll be a new toy? Would they remember bejng their previous self? In cases like I mentioned, would the pieces remember being parts of old dolls? Even after the remaking? Would it depend on the level of customizing, and if so, where's the line? Would other toys view them as some sort of abomination regardless of the answers to the previous question?

We see the Potato Head couple able to use and somewhat control their detached parts, but are they unique for being intentionally customizable? Mr. Potato Head was able to use a tortilla for a body, but would that apply to other toys? Can dolls of mixed parts even use the pieces of other dolls (like Sid's fishing rod with legs having full control, but a fishing rod is inanimate for being an accessory until it was made into a key element of a doll) or do they have to deal with those parts still being controlled by the doll they came from? What about constructed limbs made of different materials than the og body, like 3D printed, epoxy sculpted, resin casted, etc?

I have no one irl interested in this discussion, so I'd love to get some opinions, lol