Explicitly, the message is that drugs in Floyd's system might have caused his death as opposed to being suffocated (despite both autopsies).

Implicitly, it's just a more insidious form of "he was no angel", where they're hoping the jury is made up of ghouls who think drug users are degenerates unworthy of life.

For real, you don't have the right to kill someone just because you find out they're cool.