The author does not say all algae are plants. She says the algae used to make algal flour are plants. As far as I can tell, she is correct.
AlgaVia uses "microalgae", which, according to Wikipedia[1] are plants.
AlgaVia uses "microalgae", which, according to Wikipedia[1] are plants.
"Higher" here to me implies microalgae are also plants, otherwise the qualifier isn't needed.
The article for "algae" says: "No definition of algae is generally accepted. One definition is that algae 'have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells'. Some authors exclude all prokaryotes thus do not consider cyanobacteria (blue-green algae) as algae."
So it seems a little silly to me to split hairs about whether algae are plants in an popular audience news article about a food product.