The issue, in this case, isn't opinions nor the other discourse in the thread. Rather, it is the account's comments over a long stretch of time.
The question "has an account been using HN primarily for political or ideological battle?" is one of the most important criteria we use in HN moderation. When it is the case, we ask an account to stop and/or end up banning it.
This rule has many advantages. One is that it's a reasonably objective call to make (and for readers to verify) regardless of the specific views a user is arguing for or against. Another is that it allows for a certain amount of political and ideological discussion (as long as it doesn't break the site guidelines in other ways, of course: https://news.ycombinator.com/newsguidelines.html).
I have read the guide, although i appreciate reaffirming it as the source of truth. What’s hard is from a glance at the posters history their comments don’t seem to break the guidelines, but instead fall into the camp of spirited (albeit strongly so) opinions. Are there specific comments made that weren’t in the spirit of the guidelines? It feels “primarily for ideological purposes” is hard to counter in a discussion because “ideological” itself is a murky term at best.
The point is the pattern (I think the person you are responding to is incorrect about flamebait), you'd go look at the topic of their most recent comments - if the vast majority of interactions are to argue X then that seems to fall under 'idealogical battle'.
