Hi,
I'm not sure anyone promoted it for homebrewers. It's main purpose is to reduce the use of lead in consumer electronics. This is important to do. As can be seen even here on radio forums, many consumers treat electronics as disposable items -- buy the cheapest one can from China and if they don't last or don't work for our needs -- no big loss, just throw them in the garbage.
But even if they then manage to make it to a decent landfill, they need to be managed basically forever, in order to keep the lead from leaching out into our groundwater supplies. And this is in developed countries; in other ones they just sit there leaching out lead and other minerals and chemicals, or are burned or acid bathed by people trying to get any gold or other valuable metals out. The remains just go out into the environment. At least if manufacturers remove the lead from the product to begin with, that is a good start. And in controlled industrial conditions, lead-free soldering can be done pretty sucsessfully.
Use of lead solder by homebrewers is just a drop in the ocean. And it is pretty difficult to get it into the bloodstream of adults, so it's just very important to keep any of it away from the young. The main pathway is through ingestion so bits should be cleaned up carefully and not left around for babies and toddlers to swallow. Once a person is past that stage, it is unlikely they will be eating pieces of lead even if they are melting it down for hobbies. And lead only easily enters the bloodstream in not fully developed digestive systems, so adults are pretty safe. That's why lead was removed from paints, because teething babies would end up gnawing on woodwork in the house or just getting flakes on their hands and of course putting their fingers in their mouths.
73