It would've been better if I'd been more deliberate with that sentence, you're right. "money" was my shorthand for "things moving in the economy, including financial measures like cash and the exchange of goods and services". Just measuring the movement of money means that two people could create an apparently vibrant economy by exchanging $1,000 between them every minute of every day, but such an economy would be absolutely bereft of any real value or health.
"Stagnant" was my way of referring to hoarded money that's not actually invested in anything. Yes, it's equivalent to removing it from the economy and it reduces the nominal price of goods and services, which also means it reduces the nominal wages (over time). Which means old money is given a much stronger benefit in the economy when they finally spend it, and new money (including new entrants like an 18 year old getting their first full time job) are severely penalized not due to any actual lack of skill or ability, but due to their entering the economy 100 years too late.
"Stagnant" was my way of referring to hoarded money that's not actually invested in anything. Yes, it's equivalent to removing it from the economy and it reduces the nominal price of goods and services, which also means it reduces the nominal wages (over time). Which means old money is given a much stronger benefit in the economy when they finally spend it, and new money (including new entrants like an 18 year old getting their first full time job) are severely penalized not due to any actual lack of skill or ability, but due to their entering the economy 100 years too late.