I have a feeling your dislike of Trump and possibly even conservatives is clouding your judgement. Vance is well liked by basically all Trump supporters.

If Joe Biden has proven anything, it's that voters will vote for someone they barely like if they think it's helping their cause.

The only issue in play here is how many voters think lower crime, less wasteful spending, less racist hiring practices, and less illegal immigration is something they like. If they decide those things matter to them, JD is more than likable and capable enough for them to get behind.