I don't think anyone is confused that Republicanism doesn't equal Conservatism. Notice, I didn't say that I'm unsure of Powel being a Republican, I'm just unsure of him truly being "Conservative". Again, not also saying "Liberal", but at the most he's a moderate with leans equally both ways.
The issue is this move to the middle by the GOP, which I think is less as prevalent as you think in regards to the majority of its base, being found mostly in those closest to the media. While not all Democrats are dyed in the wool liberal, the parties identity and general starting point IS liberal. The Republican Party doesn't need to be ALL dyed in the wool conservatives, but it HAS to have a party identity of staunch Conservatism at its core.
The reason many people are happy to reject the moderate conservatives to liberal members of the Republican Party right now is that the parties leadership has let it lurch so far to the "middle" now that its disenfranchised and pissed off a great deal of its base and they're sick of it. They feel its time for a purge and that the only way to get back to a conservative starting point is to focus on actual conservatives. Once you relay the foundation, THEN you can start adding on those of a more moderated stance.