Think about it. As long as there are political "parties" in general, these primaries are going to keep funneling candidates down to the most extremist options possible on each respective side (the so-called "champion" of said party's beliefs), because voters HATE compromise.
Meanwhile, becausevoters hate compromise, the "moderates" (the ones who try to objectively see the valid points from both sides, and would actually be great for uniting the country as-a-whole) don't even have a toddler shit's chance of winning anything..., ever. Even if they'd be fantastic candidates in a general election, they get OBLITERATED in their own primaries, because they're seen as half-hearted to their precious party. This political system fuckin sucks!
TL;DR - Primaries / parties make it where you HAVE to go all-in with your party's rhetoric, or you lose. End of story. The only way a fair or "open-minded" candidate will ever have a shot is if the party system goes away entirely (which will never happen.) Sooner or later, we're going to get so divided that we're fucked (another civil war, assassination, etc.).
so what you are saying is that if voters were more open-minded, moderate candidates would be successful?