It may not be a dead issue but it could be a subjective one.
Thsi topic has been discussed in previous posts, a little searching should locte it for you.
We plasma cut most plates up to 1" thick and oxy-fuel cut anything over that.
We have found that we sometimes get porosity in FCAW welds if we don't remove the oxide layers by grinding. It does not happen in every case but often enough to warrant some grinding attention. Oxy cut edges have not been as much of a problem. Water-jet cutting also has given no problems with welding (not that I would think there would be).
I do not know about laser cut edges.
D1.1 allows mill scale, rust, even some paint, as long as those are not excessive and will not interfere with welding or produce objectionable fumes. You will have to check other codes for their provisions but I believe they are nearly the same.
Based on this, I would say that the oxides left behind would not need removal IF not excessive and there are no welding problems.
Chet Guilford