The Republicans aren't the only party to nominate a caricature. The Libertarians have also done so. Apparently, Johnson took “fiscally conservative and socially liberal” as a dogma instead of a dumbed-down version of libertarianism. I hope he's not pro-gun control.
Some Republicans are holding their noses and voting for the Party. Some Democrats are holding their noses and voting for the Party. I'm a Libertarian and I will be holding my nose and voting for the Party.
On the other hand, Johnson has gone off drugs for the campaign. After he's been off drugs for a few more months, he might change his mind. (In case you were wondering, my response to “legalize it, don't criticize it” is “Let's do both!”)