Article says: "On Earth, [dimethyl sulfide] is only produced by life." They also say, "The inference of [dimethyl sulfide] is less robust and requires further validation."

So they might have found evidence of something only produced by life on earth. Or maybe it was an incorrect analysis or maybe this is produced through other means on other planets.

I think the Facebook post was confused or misread the finding. CO2 and methane can result from non-biological processes.