The ethical dilemma and the crew replaced by a imposter/mind controlled/parasite/shapeshifter etc trope
The ethical dilemma of whether to move a moon that was going to crash on the planet but by doing so will doomed another planet. The senior crew must decide which planet to save
After all the debate it turns out that the other planet that would be doom just had occupants of two rich people and they were just being dicks for trying to guilt trip the Federation for rescuing the planet.
I do find that slightly funny
The joke that whether Ensign Purple hair girlfriend was replaced by imposter and then Ensign Marriner speculating whether she was a robot/shapeshifter/parasite/shapeshifter etc etc (referencing alot of episodes of Trek in the process) was also funny and what I expect from a Star Trek parody
If it focus on that, perhaps this episode could have been a good star trek parody
However the episode is destroyed by the message of the show and the sheer amount of mean spirited behind it.
You see Ensign Marriner suspect Ensign Boimler
girlfriend is an imposter solely by the basis that she can't imagine an attractive women genuinly liking Ensign Boimler
Now this could have potentially be an episode that mixed comedy with some sort of positive message if the outcome turns out that it was purely Ensign Marriner paranoia and that she really did genuinely like Boimlerthe way he is. Learn that people of all personality types can be attractive to different people and that people have different taste. You know the whole infinite diversity/infinite combination, respecting differences and unique idiosyncrasies of individual. That not everyone has to be an alpha dominant individual to be attractive.
However what happen was that it turns out that while the girlfriend was really a real human being and not the imposter. It turns out that Ensign Boimler had a parasite on him that release pheromones that caused people to be attracted to him (by the way this is a plot hole, why isn't Marriner attracted to him and why did she find it revolting seeing Ensign Boimler naked if he did have this pheromone releasing parasite on him).
So when the parasite was removed, the girlfriend immediately broke up with him and was fascinated in studying the parasite.
Let's just ignore the debates on the internet whether Ensign Boimler is a representation of nerdy Star Trek fan or not and whether this depiction is a middle finger to star trek fans as it's kinda irrelevant.
It's just mean-spirited and un-Trek like to have an episode basic message is making fun of a indivdual whose biggest crime is being socially awkward that he is destined to be loser without an attractive girlfriend. The only way he could get a girlfriend if he has some sort of pheromone secreting parasite on him. He is not a bad person just an introverted socially awkward person and having episode after episode making fun of him is of bad taste and gives a bad message and even maybe encourages bullying.
Like I said before, imagine a TNG episode where people make fun of Lieutenant Barclay for being a virgin loser.
So while this episode does do an effective parody Star Trek and isn't a middle finger for liking Star Trek (unlike the previous episode), I just find this episode inherently in poor taste, borderline immoral and encourages bullying of vulnerable people