There is a formula set by Congress long ago for determining COLA increases. There have been none recently because the pre-established inflationary figures were not met. Obama did not change this. The fact that there was no increase was according to the formula, which has nothing to do with anything Obama has done.
I do not consider a lack of a COLA increase to be a "cut". A "cut" would be a DECREASE in what I actually pay, not a lack of an increase.
I fail to see why this should be related in any way to the salaries of these temporary people in the government, This sounds like right wing crap to me, and that would be because it is right wing crap. Supposedly the government needs to pay salaries that are comparable with what the same skill set would require in a non government job. Washington DC is a hideously expensive place to live, and always has been.