If plenty of people are already doing it, why is the article titled with the question of whether we should start doing it?
It's because the article is talking about making it more of a primary source of nutrition. It isn't even the primary ingredient in sushi.
So, if the rich (and politicians) start eating it as a primary source of nutrition, then the commenter to whom you were replying might consider it similarly.
Because they are trying to sell the idea to the western countries. But macroalgae culture is a standard business in China and Japan since thousands of years.
I had eaten it, the green are good, salty when fresh and a little bland after cooking it, the red are a little bitter with a medicine aftertaste. You should use it sparsely in kitchen. Is more a spice than a main dish.
The main problems are that climate change removed 90% of the Laminaria forests here in the last 20 years and that the red algae are harvested and sold for pharma and industry, so aren't really available to harvest to the common people. You need a permit for this. The culture is also complicated here.
It's because the article is talking about making it more of a primary source of nutrition. It isn't even the primary ingredient in sushi.
So, if the rich (and politicians) start eating it as a primary source of nutrition, then the commenter to whom you were replying might consider it similarly.