Cell cultures are plain cells growing in a plastic bottle. Human cells have only a cell membrane made of phospholipids around them, which can get easily disrupted by detergents. Humans don't die when exposed to a drop of soap, cell cultures do.
That doesn't mean that a detergents can't have other effects that are harmful to humans. It just means that I don't think a cell culture experiment proves anything in such a case. A study in animals would be something different.
That's not how I'd interpret this sentence: "We have skin and other barriers that protect the cells." It sounds to me like the author claims that humans have skin, which is true, and that skin forms a barrier that protects internal cells, which is extremely plausible.
That's a literal interpretation. A contextual interpretation implies that Roundup cannot cause harm through the observed means because it cannot clear the skin, the latter of which is patently false.
No. The contextual interpretation says that the above-mentioned study doesn't prove Roundup is harmful because the same results would be observed with any detergent, to which we are regularly exposed without suffering any harm.
Therefore, Roundup might or might not be harmful, but the study doesn't tell us much about it.
> to which we are regularly exposed without suffering any harm.
Right, because we're instructed not to consume detergents. Following this instruction keeps the detergents outside the body.
We are instructed to consume food grown with herbicides such as Roundup, and Roundup is often (if not always) delivered in a sprayed manner with significant aerosolization.
