Using it to generate code isn't inherently bad (outside of copyright concerns). Especially in "stupid amount of boiler plate" languages/etc.

But the problem is that people are lazy. They don't bother understanding the output, making sure it does what you want it to, etc. It's not that different than people copy pasting code from reference material. Part of the beauty of software development is that you don't have to solve every problem someone else has already solved. But you do need to know what your code is doing and why.

Copilot is a shortcut to code that "works" with less requirement to know what's happening.