@Whatevs  
Think of it this way: Rarity learned that Owlowicious was Twilight’s new pet/assistant. That would mean that Owlowicious would probably be hanging around Spike. And Spike would naturally want to know where that fancy bow-tie came from.
 
Rarity had the best of intentions, but she was being phenomenally stupid here.

@Background Pony #A80B  
Or, “Think about the consequences of your actions.”

@Background Pony #EFCD  
So the moral of the story is: Don’t do anything nice for someone, lest you hurt someone else’s feelings.

@Whatevs  
I don’t think anyone can suggest that she did it specifically to hurt Spike, if that’s what you’re suggesting, but the end result is the same both in the canon and in this comic… it causes him to become upset and question his importance. As inadvertent as it must have been, hurting someone in a thoughtless way, here by giving someone she just met the exact same gift that she’d given someone she’d known for an extended period and who she knows has feelings for her, still pretty much qualifies as a “dick move”.

@Background Pony #EFCD  
Well kindly explain to me why it’s a dick move? Because it looks me to me more that she inadvertently hurt Spike’s feelings while trying to be nice. And in this show ignorance is accepted as an excuse since it’s such a reliable way to cause conflict.  
I agree that it was clumsy but I still don’t see how you could conclusively call it a dick move without assuming her motivation was something it was not.

@Whatevs  
That’s two things you’re wrong about in one reply. Care to try for a third?

@Background Pony #EFCD  
Nope. Try again.  
Only an idiot would take that stance

@Background Pony #A80B  
It certainly feels like there’s an extra syllable in “Owlowiscious” that isn’t in “Owloysious”, huh? Plus, our preferred spelling even looks more like “Aloysius”…

I can imagine Rarity not knowing how much the bowtie would mean to Spike, and giving one to Owlowiscious to make sure he doesn’t feel left out; still, it would’ve been nice if the writers had handled this a bit differently, yes.
 
_{And I realize this is a lost cause, but I still think it should be Owloysius.}

No matter how you cut it, giving away a copy of Spike’s gift right in front of him to someone Rarity had only known for a few hours was a dick move.

I agree. Rarity probably didn’t mean to be so insensitive. But the way it’s written, makes it look like she just already has random bowties she just gives out to anyone. That seemingly heartfelt gift to spike, was ruined the next morning when she passed off an exact replica to an owl she literally just met (she was probably asleep when twi meet the owl, so there’s no way she knew in advanced).
 
The writers probably should have had this scene happen the next night (maybe there’s a night party), that way Rarity knew in advanced, and it’d be more plausible.

I dont think Rarity meant anything by this, but rather it was a clumsy way for the writer to make Spike feel like he was being replaced

Give all the stars bowties
 
that way, when everyone is a star, no one will be