That depends, do you copy verbatim? Or do you process and understand concepts, and then create new works based on that understanding? If you copy verbatim, that's plagiarism and you're a thief. If you create your own answer, it's not.

Current AI doesn't actually "understand" anything, and "learning" is just grabbing input data. If you ask it a question, it's not understanding anything, it just matches search terms to the part of the training data that matches, and regurgitates a mix of it, and usually omits the sources. That's it.

It's a tricky line in journalism since so much of it is borrowed, and it's likewise tricky w/ AI, but the main difference IMO is attribution, good journalists cite sources, AI rarely does.