As many people know, there has been an uptick of racist and antisemitic extremist candidates running on GOP platforms this election cycle (the ADL rounds up some of them). Some of the most prominent, like Arthur Jones in Illinois, come with their own excuses: he was the only candidate on the GOP ballot in a overwhelmingly Democratic seat. In other cases, the seat is so lopsidedly Democratic that the GOP party is basically a random assortment of fringe cranks anyway, so it's arguably unfair to extrapolate.
But this is different. For one, West won a contested primary, taking nearly 50% of the vote in a four-way field. For two, while the 15th Missouri House District has gone uncontested the past two cycles, the last time there was a general election race the (current incumbent) Democrat won by a 56/44 spread. That's a comfortable margin, and in a strong Democratic year like 2018 the seat should be safe, but it is not an overwhelming figure (by comparison, the last time Dan Lipinski -- the Democrat Arthur Jones is running against in Illinois -- faced a general election challenger, he won by a 65/35 margin). Put another way, while this is a distinctively blue-tinted district, it is not the sort of place where Republicans don't exist beyond a bizarre fringe, nor is it the sort of place where it'd be implausible for the Republican to win.
So even though this is far less prominent a race than Jones' congressional campaign, in many ways its a significantly more dangerous signal. In a race where other Republicans were running, in a district where Republicans at least are conceivably competitive, GOP primary voters chose an unabashed, loud-and-proud antisemitic bigot.