The worry isn’t that the AI would suddenly become evil by some human standard, rather that the AI’s goal system would be insufficiently considerate of human values. When humans build a skyscraper, they aren’t deliberately being “evil” towards the ants that lived in the earth that was excavated and had concrete poured over it, the humans just don’t value the communities and structures that the ants had established.
The worry isn’t that the AI would suddenly become evil by some human standard, rather that the AI’s goal system would be insufficiently considerate of human values. When humans build a skyscraper, they aren’t deliberately being “evil” towards the ants that lived in the earth that was excavated and had concrete poured over it, the humans just don’t value the communities and structures that the ants had established.