Who said that? It is not a game where you assume that combat is the normal activity. So, yeah, if you want a wargame, this isn't it. Or, rather, it is a wargame with a high casualty rate closer to real war than action movies.
But..it entirely possible to have fights and have fights regularly. But you have to actually prepare for them. The game does not automatically level up your combat ability just because you exist.
Your first fight went poorly because
1) You didn't know about how to use defensive moves
2) You didn't know the rules for the weapon you were using, so it was less effective than it should have been
3) You did not have protective gear that you could have had, because you misinterpreted what "armor" means in the law level
4) You overlooked tactical options you may have had, like disarming your foe and using cover.
This is entirely normal because you are new to the system. Part of the nature of being new to a system is not knowing all the rules.
You are asking questions. That's great! We are trying to answer them.
But part of the answer is learning your options and part of the answer is "don't treat this like a combat first game". Combat is an option you will take when necessary. It is not the default action of the game. As I said above, combat is softer than real life, but it is nowhere near as soft as heroic fantasy games. Part of the answer is not to treat every fight as a fight to the death because, again, not heroic fantasy. Not everyone who does fight you wants to kill you, either. In D&D, losing a fight often means you are dead. In Traveller, it usually means you are unconscious and either tossed in the alley or captured or some other thing that furthers the adventure, just in a different way than you planned.
It is hard to get killed in Traveller unless you start playing with automatic weapons or just stand in the open without any protection and fight to the last. But if you play with John Wick style gaming (disguised armored clothing, pistols, knives, and fists) all day long if you learn how to take defensive reactions, use cover, and the like.
But you can also play Slippery Jim DeGriz and avoid fights like the plague. The rules support both playstyles.