Why must they do labor to earn money? If I mow lawns for a summer, then invest in a lawn mower which I then lease out to someone else to mow lawns, am I not entitled to the lease money because I'm not doing the labor?

Investing the fruits of one's labor is widely considered a human right, and is even explicitly listed in the Declaration of Human Rights. And hedging ones investments with gold, silver, bonds or crypto is not an unreasonable thing to do.