These things don't happen at random.
Having participated in conceptual meetings as part of my job (not TV, but the principles are the same), I promise you that there is plenty to read into a lot of the decisions that are made.
All I said was that it was a great conceptual decision to make him a Dem. In this day and age where Cheney and others have been made into the bogeyman, and Dems are looked at more as bungling do-gooders, FU being a Dem is a more surprising choice. A better choice.
I don't believe that the producers were afraid of backlash, but I'm sure they were aware of the potential for it. This type of thing is what's discussed in the conceptual meetings that I referred to. What are the possible consequences or outcomes of us choosing A over B?
And yes. I do believe that right wing media types would have whined about the negative portrayal of a Republican cheating and murdering his way to power.
They tend to be hyper sensitive towards these things as a way to whip up their audience. Even if they don't actually believe what they are selling.