In KSP's defense, there is a boundary of realism that you should avoid when it negatively impacts gameplay. And this is actually not that hard to do: even a minor (but consistent) deviation over a long period can do most of the work for you and doesn't require active steering (other than necessary corrections due to imperfections in the initial setup). This means that in reality, spacecraft tend to make their 90° (from vertical to horizontal) turn slow and steady (i.e. To avoid that, the best approach is to orient your spacecraft as close to its prograde vector as you can, because that minimizes exposure of the less aerodynamic side hull compared to the aerodynamic nose. a 45° turn) due to the stress that puts on the vehicle most importantly it's the incoming wind from still moving straight upwards (due to inertia) that is going to start beating down on the side hull (which you expose by orienting your craft away from its prograde vector). In real life, a rocket won't be as easy to turn (e.g. In KSP, a simple ascent profile is to go straight up for about 10km, and then make a 45° turn and start building horizontal speed. In regards to the ascent profile, due to the stronger craft and less fine-grained controls, KSP spacecraft are able to ascend using sharp(er) turns than is realistically possible in real life. Given a keyboard and mouse and moslty eyeballing the thrust gauge, there is only so much precision you can reasonably expect from a player. In regards to the controls, KSP's control system is not as fine-grained as a real world spacecraft.

This is all done to 'round the numbers' in favor of the player to make sure that the limited part set can get most reasonable jobs done. Engines are also more powerful, and fuel is (slighly) less heavy. The tradeoff here is that when something finally breaks in KSP, it explodes and disappears. In regards to the engineering, KSP makes its parts much stronger than the real life components. In regards to the physics, KSP is fairly realistic, other than it not modeling n-body physics (which isn't really relevant in scope of orbiting Earth/Kerbin).

Kerbal space program gravity turn