Would you prefer they complicate the discussion by trying to explain what they are? My understanding has always been that they have many plant-like characteristics, but not all. In fact, they are even a part of the plant kingdom. https://www.sciencedaily.com/releases/2007/06/070619182508.h...

Some are, some aren't. Upon further research it does appear the type used in this algal flour are related to plants but many algae species aren't closely related to plants at all.

https://en.wikipedia.org/wiki/Viridiplantae

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.

https://en.wikipedia.org/wiki/Microphyte

Perhaps it's been changed since you posted this link but I see nothing about microalgae being plants.

From the article: "Unlike higher plants, microalgae do not have roots, stems, or leaves."

"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.

Some algae are, and some are not. For example most green algae are still considered plants.

Plants generally aren't grouped with green algae despite them having evolved from a common ancestor. I guess it's a bit like the crustacean/insect division, so maybe I was being a bit too facetious.