Yeah, Kemp is just that bad. But Bohm is also the better/more experienced 1B so it's more about putting the rookie where he's most familiar.
Kemp is definitely not better than Schwarber in the OF either. The only reason not to do that IMO is because DH has obviously been great for Schwarber's bat and base running (relatively speaking) too. But until Kemp hits and Harper comes back it doesn't matter.