Yes this is a reasonable way to misunderstand given the way we refer to “hard sciences” and “soft sciences”, but it does not map to the terms “hard scifi” and “soft scifi” in common usage.
It’s not exactly about rules consistency either as stated by the GP, though that’s part of it. It’s more about strong consistent application of scientific principles even theoretical or untested principles.
This is in contrast to futuristic fantasy with no real focus on the science. But futuristic or space fantasy can be very consistent just like magical systems in fantasy can be very consistent. Hard scifi has to be constrained by plausible consistent science and that science is typically a main character in the story, or even THE main character.
It’s not exactly about rules consistency either as stated by the GP, though that’s part of it. It’s more about strong consistent application of scientific principles even theoretical or untested principles.
This is in contrast to futuristic fantasy with no real focus on the science. But futuristic or space fantasy can be very consistent just like magical systems in fantasy can be very consistent. Hard scifi has to be constrained by plausible consistent science and that science is typically a main character in the story, or even THE main character.