Don't let comments on Hacker News unduely influence your website decision making. The issues raised here tend to be laser focused on things that likely won't correlate with your success in the market.
You'll never be able to please everyone so your ability to study and run experiments is key. If anything, it sounds like you are doing things exactly the right way.
Very good answer. By these time of GDPR and privacy protection, it's super important that open source/free software project be absolute models in those areas. Indeed, when I recommend using free software like LibreOffice, its in great part because of the trust I have in your code (trust that I won't be fd now or in the future). Uncompromizing handling of cookies is part of that trust. Thanks for your wonderful job !
edit: in case it's not clear : i'm all for appropriate tracking (in your context, improving the website), provided that 1/ I know about it 2/ I have a choice (in your case, I'll opt in* if I can)
You'll never be able to please everyone so your ability to study and run experiments is key. If anything, it sounds like you are doing things exactly the right way.