Apparently she hasn't been charged yet, she's currently being investigated, but it seems that RICO is the framework that they are considering using to charge her.
How so? If this case sets a precedent that anyone who speaks out in favor of marijuana can be prosecuted as part of a criminal conspiracy, then by defition they would be eligible for the death penalty because that's how RICO works- you can get charged for any crime committed by someone else in your 'organization', regardless of what that crime is or what penalty it carries. I don't see how that's an extrapolation.
You've extrapolated from a single question from a single investigator to a nonexistent death penalty case and pinned it all on an imaginary Obama administration mandate to charge everyone involved in medical marijuana advocacy. That's not the story here.