> Every post should have a set of tags: describing the subject. In the information overload age filtering is becoming essential.

You state that as a fact, but it is an opinion. I think using a filter would prevent users from seeing posts and comments that they would find interesting. In a sense, it would create a bubble for each user.

Also, HN isn’t that large that a quick visual scan of the home page doesn’t work.

> If readers don't want to use tags/filters they don't have to.

And if writers don’t want to use tags, or can’t even remotely agree on which ones should exist?

For example, in your example list, Code and Software would have significant overlap, AI about always would be software, Politics should be very rare according to the HN guidelines, people would disagree about the definition of Startup.