no, people can still buy whatever the fuck they want on the internet since these laws are categorically not enforceable.

Since the EU can't ban manufacture in non-EU countries either and there's no way to effectively check individual parcels, banning all glitter manufacture would have the same issue, people would still be able to buy this stuff on foreign websites.

If you can understand that, I don't see why you're confused by the same exact principle being applied elsewhere

Because it's not the same thing. This affects manufacturers of products containing glitter. Consumers are only affected insofar as they can now either go out of their way to buy glitter for canonically ugly crafts projects (passing judgment here) or produce slightly less ugly crafts projects without glitter.

I am not going to argue that producing this legislation is the wisest use of EU bureaucrats's time. It's certainly not. They could have worked on regulating the single biggest source of microplastics, i.e. car/truck tires (via car weight reductions, tire formulation regulation, or even a small vacuum behind the wheels). Or they could have gone for cosmetics (where you can just ban them outright for a number of product classes, e.g. shampoo/shower gel is used a ton and simply doesn't need silicones etc.).

But I also do not see it as a blame-shifting piece of legislation. They just chipped away at an easy target that does not have much lobby, unlike with automotive or cosmetics topics.