I still don't see a decent reason. You can't just say well last time we tried to Evac, ppl died and the hurricane wasn't that bad! If the govt wants an evac it should be done in an orderly fashion, e.g., have both directions of interstates be changed to one way exits, have LE agencies coordinate timeframes of evac by certain regions/zip codes. Most importantly, the key should be to have evac plans spread out over a period of time so no one feels like they all must blitz at the same time. The deaths before with the bus fire was tragic, but that's a one off event. Running out of gas shouldn't happen if ppl were prepared (who doesn't stock up on food or gas in a high risk area?)
Problem with Harvey is a couple days before it hit, the NWS and even CNN weather were saying the most troubling aspect of this hurricane is then once it makes landfall, the computer models show that it stalls. And that stalling without continuing inland means the storm is going to be remain strong as it drops tremendous amounts of rain, let alone wind damage. If the govt didn't order an evac, this should still have been alarming on an individual level.
Right now they're reporting many deaths with people driving (in control) cars into flooded streets/waters and their cars being swept away. Quite a few deaths like this already, this was preventable.