This site is a very good liberal-progressive political opinion news site. It makes no attempt to hide it's bias, so there is no ethical issue with having bias if you place it up front.
There is no attempt to hide the bias, so if you don't agree with it, just don't read the site.
All of the tracking cookies are from add and analytic providers that do honor my opt outs, unlike some other news and opinion sites. The only information kept in the site's cookies are my first hit on the site, and my session index data.
I do not see any ethical issues on this site, the only thing I can come up with are that the complaints may be politically motivated, which makes me question the ethics of the posters.