They're bad right now because guys like Julien, Buxton, Jeffers and Wallner have not been very good (some downright atrocious). And Lewis being hurt. These are all guys that were expected to be key contributors regardless of the offseason moves.
I get the frustration with the offseason and I agree with it. But if they had signed Montgomery, that doesn't change how bad the hitting has been. The hitting is the reason we're losing right now much more than the pitching. They've scored a grand total of 10 runs in their 6 losses.