If I live in the woods alone, hunting and gathering my food and felling my own timber for firewood and construction, then that is my economy. Economy means how a society allocates their resources. If I live in a one-person-society as a hermit, then me gathering and hunting at least enough food to stay alive and having enough resources to keep my abode able to protect me from cold and rain is my economy.
As economy means simply allocation of a society's resources, it is not possible to not have an economy. There is always an economy. But, it doesn't need to be based on money, necessarily. Any system where goods are distributed to people who need them is an economic system.
So, the OP is misunderstanding the word "economy", but the main point of course still stands: The monetary economy as we see it in our current society is actually purely a social construct. Or simply: "Monetary economy isn't even real, we literally fucking made it up" is correct.
But economy is real.
No. But I do get why you'd ask :)
The thing is, for toppling the current economic system, it would be important to understand that there can be different economic systems. And also, that it's not a choice between only capitalism and communism, but that there is an infinite amount of other economic models to invent and use. And their subtypes.
Understanding economy as a synonym for our current money-based economy is strongly in the interest of those who want to keep the current system unchanged.
If you don't understand why having an economy that is thought of is important, you cannot get any useful results by toppling the current one.