I'm a chocolate fan myself and it was something I used to buy often, but just as I started getting into the hard stuff (80% or higher) I learned about all the problems with heavy metals in dark chocolate and specifically in Lindt, and then later learned about the use of child slaves which is an industry wide issue and not exclusive to Lindt/Russell Stover/Ghirardelli/Lindor although Lindt and Hershey are reportedly worse than other brands.
You can find brands that claim to be more ethical in terms of sourcing their cocoa, but the smaller brands that do are also less likely to have been tested for heavy metals.
While it's unclear how harmful the heavy metals would be to me specifically at the amounts I was eating, the whole thing kind of put me off chocolate in general and dark chocolate in particular. I rarely have it anymore.