If you've learned the material and fulfill the requirements, and the course is still ongoing, why should it matter you were late? Are you teaching the subject, or is [literally every course all the time] really mostly a study in time management? (hint: it's not for the student's sake, it's about managing teacher time and resources. Which is obviously necessary, but not otherwise positive)
> That reinforces that idea that it's okay to do a half-ass job because you can always "fix it later".
I'd say it might equally mean not pointlessly throwing in the towel and phoning the rest in just because you performed poorly early on and (rightly) feel like it doesn't matter anymore.
> In the real world however, poor decisions can have devastating effects the very first time, and there might not be a chance for a "do-over".
Sure. Exceedingly rarely though, compared to school.
> Homework also normalizes the idea that things will be expected from you in this world if you are to be employed.
Most jobs don't involve additional work after you've finished work. Nor constant artificial deadlines that never let you truly relax. Constant stress is bad for humans, it's not something that hardens you, and pointlessly subjecting people to it "just because" is not just useless but counter productive, because you get blunted. It's important to have something extra to tap into when shit truly hits the fan and it's time to step up, but the contrast gets lost if it's a neverending blur.