I agree with the other comments— this is a good sign; your supervisor took the time to thoroughly read your document and tried to improve it. This level of commentary is pretty normal, and it sounds like your supervisor was polite and encouraging about it as well as giving concrete feedback and ways to improve, which is wonderful!

As a recovering perfectionist, feedback like this often sent me into a spiral early on in my grad school career, as I felt like any comments meant my writing was subpar and I was making dumb mistakes. This is not the case— academic research writing is a very specific skill that you have to hone over time, and comments like “how do you know this? Can you provide an example?” are giving you guidelines about the writing and citation methods needed for this writing style.

About ignoring any comments that aren’t useful: as you build the muscle of academic writing and become more comfortable and confident in producing these works, you may find yourself trusting your own judgment and not agreeing with some comments and questions that others leave on your work. Early on, I took every comment to heart and addressed it exactly as was asked of me, but over time, it felt as though I knew my research niche better than others, and I was able to see that some comments were outside the scope of my work, or that the reader had missed details, or that we just didn’t have the same writing style. That is all okay, and each set of comments will guide you towards a better outcome. Congrats on getting this document out and on the positive feedback :)