I think the appropriate term for this scenario is "trap".
The threat level only describes the site at the time of scan. What happens after you enter the scene is.. well.. random. Is it unfair? Yes, it is. Most things in Elite are.
As for being deaded by two shots -
1) What suit are you wearing? It most probably has a shield. You have to switch it on, though. It's off by default to save energy, unlike in the ship.
2) Look for higher-grade suits and weapons at starports. They're worth the money.
3) Cover! There's always a crate or a wall you can put between you and the other guy.
3.5) Bringing an SRV into the fight is also a valid tactic.
If you want missions where nobody is shooting at you, you can find simple fetch quests all over the place. They usually take place at secure bases where you only have to find the correct crate, take the thing and return with it.
Unless you do something naughty (like stealing or not stopping when a guard wants to scan you), you won't have any trouble there.
You can always do the shooty stuff later when you have the right equipment. Just like in the base game. You wouldn't go into a hazardous RES to hunt Anacondas in a Sidewinder.
Well, maybe you would. I wouldn't. Coz I suck.
TL/DR: Yes, the intent of the expansion is to hone your skills and patience through adversity and obstacles.

It is made to throw even the most hardcore Elite veteran out of their comfort zone and force them to... ehm.. have fun. Or something.