I would just mind my own business if it wasn't effecting me. Unfortunate, the chemicals from Roundup, and Weed and Feed products are showing up in our city water supply. The City of Austin has requested that we (residents of Austin) quit using these products because of the water and also because of the numerous trees that we are bless with in Central TX.. My neighbor was going to use Weed and Feed on his yard close to where I have a grove of live oaks. Fortunately, we talked about it and he agreed with me. The city mailed a brochure explaining how these products are harmful. You may want to take your complaints to city hall.
You're right about using any product that may contaminate the environment. I admit to using a very small amount of bleach (1/4 cp per load of whites). We have a high efficiency washer that uses a lot less energy, water, bleach and detergent. But that is like being a little bit pregnant. I'll see if I can get along w/o the bleach.
Please, please discontinue using Roundup. Try using natural herbicides if you must. I've never used some of the organic suggestions (never needed to) but as I understand they are as effective without the disastrous effects.
The vegan example is a personal choice as I see it. To each his own and more power to them. But if that vegan uses Weed and Feed near my trees I've got a problem with that.
Have you ever considered how many people use Weed and Feed and Roundup and have never even read the instructions? I'm particularly worried about his because of the large number of illegals we have in Austin.