They were wrong, in that I think they read something similar to what you linked and completely misunderstood what it was saying to mean "the EV engines turn tires into cancer poison," rather than "EVs put more stress on their tires as byproduct of their weight, which in turn can release carcinogens."

The Chevy Bolt weights about 3,600 pounds - while heavy for a vehicle of its size, it is not particularly different from an average "midsize" car weight, at least according to Google. This seems like a red herring to me given how much larger most cars on the road are, at least as far as the Bolt is concerned. Perhaps it is an issue for larger EVs like the Model Y or Mach E.