Well… by The Global North, anyway

And Elon Musk is responsible for like half of it already.

Whole satellites no, its when they start to break up and create a perpetual shotgun blast of pellets moving hundreds to thousands of meters per second that take years to deorbit and are too small to track effectively (or at all).

On their own they’re not anything particularly terrible, but it’s the face that so many are left up in LEO that presents an issue. Kessler Syndrome is an even that occurs when a cascade of space debris will make it impossible to have anything in orbit or for us to have anything leave the planet because for example, if a bolt from an old satellite gets knocked off by a meteor it’s travelling at extreme speeds carrying a bunch of energy. Once that bolt then hits another satellite it might knock off a dozen small pieces which all go to knock off another dozen small pieces and rather rapidly there’s so much small debris that it’s shredding anything in orbit. Even without Kessler Syndrome it can lead to potential dangerous events like if we have a space station, having it potentially destroyed by trash that is flying about.

https://en.m.wikipedia.org/wiki/Kessler_syndrome

Just off the top of my head, they are a collision risk and pollute the night sky (for those to who that is important)