>Is there a reason why an AI being trained on the same open source code isn't a similar situation?

You are a human. You know what's right or wrong. You know you can't just copy code 1:1 from public repositories without respecting their license. The AI doesn't know and doesn't care. It's a common problem with creative AIs that they will occasionally regurgitate near 1:1 copies of their training data, and I don't think it's an easy problem to solve.

>I agree that wholesale pasting of code chunks is an issue, but that hasn't been my experience with Copilot.

The article provides several examples of it happening. Just because it hasn't regularly happened to you doesn't mean it doesn't happen.