This isn’t exactly surprising. Culture war above all. A possible steel man might be that in a first past the post system two major parties developing is inevitable. After that it is often more expedient and within your self interest to attack the opposing party when the opportunity arises. User OursIsTheRepost, in the The Intellectual Dark Web subreddit, 03 May 2019
"partisanship rather than moral foundations drives most of U.S. voters’ responses to moral foundations violations by politicians." User lunaranus, in the The Motte subreddit, 02 May 2019