Because lead poisoning isn't a huge issue for hobbyists.
Common rules are: Work in a well-ventilated area, don't eat while working, don't use your soldering iron to heat your coffee. But those apply while using lead-free solder as well.
Common rules are: Work in a well-ventilated area, don't eat while working, don't use your soldering iron to heat your coffee. But those apply while using lead-free solder as well.
edit: so, it's the frequent repeated exposure to lead (i.e. in paint and as a sugar added to wine[0]) which is harmful, not any single individual (non-acute) exposure.
[0]: https://en.wikipedia.org/wiki/Lead(II)_acetate#Sweetener