Oh what a clever way to insult me and yet offer know explanation for what it means to you at the same time.
You just insulted everyone who is using the common understanding of the term.
Mmm I wouldn't know because people keep using the information at their fingertips but not using their own understanding to explain 🤷♂️ information, knowledge and understanding, three totally different things yes?
It's extremely common to grab the dictionary definition of a word one is familiar with rather than coming up with "their own understanding" on the spot because the dictionary definition is derived from the common understanding. It shouldn't be surprising that most people would then be inclined to site the dictionary. It matches most people's understanding.
Nobody thinks that muscle memory means memory stored in muscles. You insist the words mean this. That implies that everyone is using the term incorrectly. They're not. Muscle memory is just a descriptor for the particular effect training/learning/practicing a physical action enough that it becomes something someone does without thinking about it as part of an overall action.
If you have a problem with a phrase because you think it misleads the hoi polloi or it's just one of those things that drive's subject matter experts up the wall because it's an oversimplification or 3 degrees off true, that's fine. Just don't run everyone down for using it.