This is incorrect. To be a furry, you have to enjoy content containing anthropormorphisized animals, which means the animals gain traits that are typically for humans. Though this usually depicts bipedal & humanoid animals, any human trait, such as speech, societies, religions, literature, etc., when given to an animal, means that said animal has been anthropormorphisized.
Many fans of literature, theatrical, and art pieces, are, by definition, considered furries, because, as I said before, the enjoyment of content with anthropormorphisized animals makes you a furry. So fans of Wings of Fire, Warriors, Seekers, The Inheritance Cycle, Narnia, The Lion King, Zootopia, and many more are technically furries.
While many furries have fursuits and fursonas, it isn't necessary to have these to be a furry, though I believe that OCs for these fandoms could be considered fursonas' --- I'm not sure about this part though