Adding to other's responses, exploding thing at geostationary orbit is especially bad:

1. there is roughly only one such orbit
2. because of (a) it is much more limited in terms of amount of spots for satellites distant enough from each other to be considered safe (imagine beads)
3. because of orbital mechanics destroying things creates cloud of debris that eventually takes up form roughly similar to torus, embedding original orbit, endangering all other satellites here and threatening to start chain reaction of creating more and more debris from collisions
4. this orbit is quite high and atmosphere here is so miniscule it'd take hundreds and thousands of years for that debris to meaningfully slow down and drop to lower trajectories; and junk that got higher orbits will decay even slower. It's not coincidence that graveyard orbit for geostationary satellites is higher

All in all, don't explode things here

All orbits require very minimal maintenance, the closer to earth, the more maintenance required . Far enough out, and its basically maintence free, except for avoiding other debris.

The problem with an explosive self destruct is that not all debris will go down into lower orbits, some with go higher and therefore take even longer to deorbit. Its also a lot easier to track one dead satellite instead of thousands of minute particles.

And ideal "self-destruct button" would actually be a thruster firing in the direction of travel, which would slow it down and drag it into the earth, or if facing the other way, boost it up to a "graveyard" orbit. Both these exist on many satellites already.

Sorry to disappoint, but exploding something at GEO would make things worse.

All satellites in orbit of Earth will experience atmospheric drag. Even the Moon is bumping into gas atoms.

Geostationary satellites will eventually fall. It might take millions of years, but eventually the thin atmosphere will slow those satellites down enough that their orbit will fall into the thick, lower atmosphere where they'll burn up or crash into the Earth's surface.

Exploding a satellite up there will just make a shotgun spray of projectiles that will still take millions of years to fall. Assuming the projectiles shoot off in all directions fairly evenly, then the ones that get shot backwards relative to the motion of the satellite will end up in a lower orbit that will decay faster. The pieces that get shot forward might actually escape Earth orbit all together and become little asteroids orbiting the Sun.

The thing that's special about geostationary orbit isn't that the orbit of things at that altitude does not decay. That altitude is special because at that altitude, orbital speed is equal to the Earth's rotational speed. A satellite at that altitude over the equator will remain over that same longitude - it won't rise and set like the Moon, it will remain in the same spot overhead both night and day.

This is so dumb it's almost brilliant. If you go to a job, you're working class. If you make rules, you're the ruling class.

Nope. Orbits are defined as being passive and repeating trajectories.

They're also the default way things move in gravitational well, unless there's a collision or thrust. To be clear, geostationary orbits are way further out than the standard low-Earth orbits, like multiple Earth widths away. So, deorbiting a satellite from there requires a very sustained rocket boost, and if you just blow it up you'll get a slightly wider debris field of junk in random orbits and very little if anything re-entering.

It's a bit of an interesting aside that how easy orbits are to find is important for there being planets in the first place, or even galaxies. A collapsing cloud of dust and gas would end in a lone star or black hole every time, if some of the infalling matter didn't get "stuck".

When possible, deorbiting for safety is a standard thing, though. At least now that we worry about too much space junk; the Apollo engineers weren't thinking about it yet. It's always done by thrusting into the atmosphere.

Edit: And for geosynchronous satellites, they actually just move into a slightly higher graveyard orbit so they're at least out of the way.