Because that's clearly the standard that BioWare have set for themselves. I think the countless action-oriented demonstrations during previews, the increasing number of concessions made towards shooter mechanics, and multiplayer prove that.
It tells us that the action is the part they want to sell. Any supposition about why that is is merely guessing.
Maybe the action fans are the larger audience. Maybe the action fans are more receptive to promotion.
That just seems hyperbolic. I don't know how any single incongruence damages the plausibility of a setting to the point where you find roleplay utterly impossible. Like plot holes, these things are bound to happen and are potentially unavoidable, so in the grander scheme of your roleplaying, could you not just ignore them?
As long as the inconsistency isn't relevant to the decisions my character is making, that's exactly what I do. Or I headcanon explanations, which works until the game's explicit content contradicts me.
And that's when roleplaying breaks. Going back and recomputing every prior decision to ensure coherence with the new evidence would be a monumental task.
On a moment-to-moment basis, your suggestion works. Retroactively, it doesn't.
And if I just pretend I have a coherent basis, ignoring possible errors in the past, what am I really doing? I'm no longer roleplaying the same character. So what's the point? What can I learn from this process without a control?
Look at roleplaying like a science experiment. If the game starts messing with my variables, the results will be meaningless.