You just seamlessly switched from plastic straws specifically to all microplastics from all sources. This is exactly the sort of thing I'm talking about. How much do plastic straws contribute to microplastics? It's utterly negligible. But it's something that a public panic can be whipped up over, and people end up thinking they're actually accomplishing something meaningful by switching to paper straws. It's outright counterproductive. If I was a Captain Planet villain then I would consider it my greatest accomplishment to get people worked up about plastic straws and thinking that they were significant.
Same here with these fibre optics. The environmental impact is trivial, be it plastic or glass. The cost of worrying about it is far greater than the cost of just going ahead and using it.
It's self-inflicted.