-core suffix means that the aesthetic is centered around the prefix or things in relation to the prefix. Example: Cottagecore is centered around a romanticized interpretation of agricultural life, cottages are a way to escape technology, enjoy nature and a romanticized version of simple living.-H

To further expand on it, the -core actually stems from the Hardcore movement in punk music (hence why there are so many aesthetics that end in -core) which kinda adds something of an edge and counter-cultural vibe to it.

I mean, if they want to I'm not bothered by it.