MSTO said:
Is it even appropriate to conflate MordeTwi with "meme"? ...

Just tag Mordecai and Twilight Sparkle characters and don't use the mordetwi tag. The tag implicates meme, so if the tag is present then meme will also always automatically be added. You can't remove it unless you also remove the Mordetwi tag.
I don't believe the mordetwi tag even is valid unless the art includes aspects of the meme (ie the lyrics, space aesthetic, etc.). If you believe the implication should be changed/removed, you can create a discussion about it in the forum or discuss in the discord, and then a BUR for users to discuss and vote on it further. In this case it would be unimply mordetwi -> meme

jerdude002 said:
I don't believe the mordetwi tag even is valid unless the art includes aspects of the meme

No, no, no! MordeTwi is a pairing (ship), not a meme. "Airplanes" is not even supposed to be relevant here!
If we're talking... tagging about the meme itself, the appropriate tag name would be Airplanes. I mean, that was even the literal title of the original drawing, the "MordeTwi" part is just parenthesized – an afterthought.

Like I said: not every MordeTwi art is the Airplanes meme. But also: not every Airplanes meme art is MordeTwi.

Thanks to telling me what to do, though, I appreciate it.