I've noticed that the Republican party has schisms and arguments within their own party quite often, and the Democrats exploit that and say "they're at war with each other, they're unorganized, they are falling apart!"
In my opinion, that's the sign of a healthy party (although I despise most of the Republican party anyway lol, so I should say "healthier party" instead of "healthy"), whereas a party that has no large divisions within itself appears to be more like a "programmed" or "robotic" party that accepts everything their leadership says as absolute.
Divide and conquer. Democrats try not to show weakness or fracturing because it makes them look more like the "solid" party. They can then exploit that by telling your average Republican citizen, "Look, your party is falling apart! Join us, we don't have these problems!" It's basic warfare: You puff yourself up to look bigger than the other guy.
Republicans have gotten a bad rap lately - much of it is justified, much of it isn't - and I'm certain that strain wears on you, if only on a subconscious level. By looking bigger and "better" (I use that term highly subjectively), the Democrats can get a bigger vote.
Or I'm crazy.