Did you read the whole article? They followed up by exposing kidney cells to the extracted micro and nanoplastics and they caused significant amounts of cell death. There is definite evidence that something in these plastics is causing harm, and more study is definitely warranted.
Not exactly the best example, since that’s not a typical behavior but a result of poor scientific practices. Mantises only take that action when extremely stressed, which is frankly a lesson we should be carefully considering.