We’ve been opening and closing doors for even longer and yet it has still posed a challenge for SpaceX when dealing with the payload door on Starship. Space makes even trivial things hard.

Sure. But they gotta fix the door, either way.

Winching stuff out of said open door seems like a much, much easier task.

The satellite door is completely different from what they'll need for MarsShip, that's even larger and has to function as an airlock. None of what they're trying to do now matters for the Mars door.

That's a lot of certainty for something that hasn't even been designed yet.

The outside door needn't be part of the airlock. It's certainly big enough to have an internal airlock leading to depressurized internal space.

The things that make a door that tests fine on Earth break in orbit are likely to be things that need fixing for a similar door on Mars. They won't be all the same challenges, but some will absolutely be shared.

On another planet as their only way on or off of the spacecraft is a whole different level of risk.

Everything's a risk nine months from Earth.

A hatch with a winch (or two!) seems likely to be one of the smaller ones.