Edom bypass

Numbers 20:18, 21:4 - But Edom answered, "You may not pass through here; if you try, we will march out and attack you with the sword."

They travelled from Mount Hor along the route to the Red Sea, to go around Edom.

I wonder why the Israelites asked to go through Edom in the first place. Sure, it was a more direct route to Canaan and perhaps easier terrain to navigate, but what was the hurry? They had 40 years to get there. And if Canaan wasn't their immediate destination, why did they still want to go through Edom?

It's hard to blame the Edomites for not wanting 2.5 million people traipsing through the countryside. Even if they stayed on the king's highway, what kind of condition would that road be in several days or weeks later after an entire nation walked or rode it from one end to the other?

I wonder if the Edomites were thinking, "They'll stay on the king's highway? Yeah, right. They stayed on the dry ground walking through the Red Sea and look where that left Pharaoh's army! We can't afford to take the risk. Send them around on the bypass."