gotta say this argument doesn't hold water.I get what you're saying, but there is a huge difference between dumping something that is food and will degrade quickly, and something that is toxic and has a half-life of 24,000 years. Huge difference. And I know you know that.
Yes, the "spitting in the ocean" argument is a bad one in a lot of instances. I don't think it is in this one, considering the volume of yeast on a homebrew scale, number of homebrewers who dump yeast outside, how frequently they dump yeast, geographic distances between them, and the fact that it will readily be healthy food for other organisms. Crank up any of those factors and it might be bad.
If I have told myself once, I have told myself a million times. 'Don't be hyperbolic'
point taken and fully conceded. I dump my yeast in the compost or on the lawn and it I am sure washed into local water ways and/or sewers. but mostly eaten by other life forms