Could that light over Los Angeles have been a satellite?

There isn’t enough here to identify it. A useful report would include the exact time and viewing location, which direction it moved, how long it stayed visible, and whether there’s a clear video. Without those details, “surveillance” is a guess about its purpose, not an explanation of what was seen.

For a satellite possibility, the time and location matter more than a general impression of how it looked. A known satellite pass can be checked against those details. A short clip showing the motion may help too, though a light in the sky by itself won’t tell you what the object is doing.

I’d keep the explanations open for now. Satellites, aircraft, and other ordinary sources can look unfamiliar from the ground, and the post doesn’t give enough information to choose among them. Claims about monitoring people or intervening in a nuclear launch go well beyond what a sighting alone can show.