Obama made clear as early as the 2008 primaries that he wasn't going to be very good on civil liberties. (But he didn't have to be this bad.)
What valid concerns did Republicans have during the past eight years? Do tell. I've not heard of a single one.
Trump is the inevitable outcome of 50 years of racist, belligerent fear mongering and bad-faith governance on the part of the Republicans. You can draw a straight line from Nixon through Reagan through W. to get to Trump. Obama had nothing to do with it.