Satellites don’t include light sources and there’s nothing to illuminate them when in earth’s shadow. In order to interfere with light based astronomy they need to be outside of earths shadow and someone needs to be actively taking a picture of that chunk of sky. As these satellites orbit eye close to earth almost the entire sky is clear near solar midnight.

Major ground based telescopes can also add a shutter to block light detection for the fraction of a second a satellite would interfere. Basically at extreme magnification you’re looking at an ever smaller percentage of the sky which means the odds of a satellite, even one of millions, being in the shot for a given second is low. It’s still an issue, but being 99.X% as effective is good enough not to be a major concern.

Where it’s a concern is whole sky observation where you can’t easily add a shutter and losing a significant portion of the sky every night is a real problem.