Do I believe that the Galactic Government is involved in Time Changes here on Earth?

 Yes. But only when absolutely necessary to keep the ecosystem alive and well and to keep humans from completely going extinct.

Mostly they seem to believe that keeping the ecosystem basically intact and some humans alive on earth to be necessary. So, they prevent nuclear wars and things like this. However, for example, they wouldn't stop 90% of humans dying from ecological collapse but would prevent the ecosystem from completely collapsing.

However, it might be important to consider what happened to the dinosaurs too.

However, if you consider the war on the planet Maldek where most of our humanoid genetics came from originally, the galaxy did allow all the larger dinosaurs to die in that piece of Maldek when it flew apart hitting earth 65 million years ago and killing all the larger dinosaurs that didn't move into the oceans and other waters to keep warm enough to survive.

So, that is something to consider too.

However, even that likely was done so earth would be safe enough for the survivor colonists from Maldek and Mars after the planet Maldek flew apart and pieces of it destroyed the atmosphere on Mars which then prevented Martians from breathing and living in their air and environment to where to survive they had to move to earth too.

So, genetically we were genetically engineered as Humanoid-ape beings related to the Martian and Maldek humanoids but we didn't die from Earth diseases as much because we had the immunity from apes in our genetics. So, eventually all the pure blood Martians and Maldekians died out from Earth diseases and we were left to colonize earth by ourselves without their intergalactic technology.

Only now millions of years later are we developing our own Intergalactic technologies to once again return to the Stars of this galaxy and beyond.