The report raises the "need for a method to more effectively signal a runway closure to pilots when at least one parallel runway remains in use" and seems to focus on a more conspicuous X marking, and the ludicrously antiquated NOTAM which goes without saying. It seems the DAL521 FO's recommendation to ATC to "turn on the lights for RWY 28L" would have averted this incident. But that seems to have been overlooked in the report as a strategy. The other thing I don't understand in that respect is the DAL521 captain stated that the sequenced flashing lights were not operating on 28R. The report covers the incidence of runway lighting colouring being mistaken in other incidents, and talks about the possibility of aircraft lighting being mistaken for runway lighting. Despite all that, the report rules out airport lighting as a factor in the incident stating it was compliant with regulations. It seems to me airport lighting is a significant factor in this incident. The report quite rightly talks about expectation and confirmation bias but it seems the lighting aspects have not been given adequate emphasis. It's hard to imagine this incident would have occurred if 28L lights were on and 28R sequenced flashing lights were operating.