So, let's get that out of the way first: i don't know whether that is intended or not, but that second sentence is basically just an insult. If it this post is meant to express your disappointment with a design decision, feel free to just post it as such.

Now, to the actual question: i assume that the intended experience in that part of the game is not one of precise spaceflight but rather more akin to ocean-based ship fights with basic outmaneuvering and dynamic fightstuff. The section really reminds me of the Sid Meier's Pirates type of gameplay. So, basically the same reason "planes in space" is a thing in more arcad-y space games.

Which is a design decision you are totally free to not like at all

A design decision which I am indeed free to not like at all. In fact it baffles me as to why it is so. So baffled, that such a mechanic leaves me soft-locked when colliding with certain space ships. Not to mention poor control of navigating the asteroid fields. I'll just have to live with colliding with asteroids and being unable to get away from ships it seems.

it was an active decision by the devs not to add reverse thrusters, as to why I don't remember exactly, maybe because they didn't want to make it too easy.
But I don't think they (the reverse thrusters) are needed because flying the ship through an asteroid field is pretty easy, as for me I rarely collide with anything

Why is turning around and thrusting in that direction to reverse momentum so hard?