Beware of the confirmation bias, it works both ways. Reporting might be alarmist (it always is), actual research is largely not. This study doesn't discredit the entire field, it's pretty obvious that microplastics are everywhere and different types are harmful to an unclear extent, even if the amount might be overestimated in some studies.

>This type of research requires very little creativity or study design -- just throw a dart in a room and try and find microplastics in whatever it lands on. Boom, you get a grant for your study

Precisely, and mapping of that kind is entirely valid and required in huge amounts to have the full picture. Somebody has to do the grunt work.

Unfortunately too often authors of non alarmist research end up promoting alarmist interpretations of their work in science media.