I do understand your exact point. This wide umbrella of "everything is politics" is akin to "all roads lead to philosophy" : https://www.xefer.com/2011/05/wikipedia
That said, I can also what understand what people mean when a dinner host says, "let's not discuss politics". (Previous comment about that interpretation: https://news.ycombinator.com/item?id=14473441)
Even though I perfectly understand what roenxi means by "You can't discuss anything important and uncertain without running in to politics.", I'm still able to grasp what the dinner host means by "no politics".
Likewise, the HN moderator dang tried the experiment of "no politics for a week". However, people didn't want to use the "dinner host" meaning and would rather litigate on the "but all roads lead to politics" meaning to make dang look naive in his social civility experiment.