Because what a bunch of people sitting in chairs think makes it scientific.
If something is true, it ought to be true regardless of what anyone thinks.
The proper way to science:
1. Publish a paper stating a hypothesis (gravity doesn't exist, it's just buoyancy and propulsion based on objects being light or heavier than the air pressure)
2. Okay, prove it. Make an experiment with these peers watching (a gigantic fish tank with artificially pressured water and air, and wild caught fish and birds. If the fish are unable to swim below a point this is buoyancy. Likewise if birds are unable to fly where the air is thinner than them, then you have basically your theory. If gravity exists, then something will interfere despite the careful pressure control which costs billions in taxpayer money)
3. At least on of the peers tests this in a different location to see if there was any sort of climate interference, if you faked anything, stuff like that.
4. If for some reason, you can't show an experiment proving your theory (like being poor and not a scientist), then the real scientists get to sneer at you, and ignore your theory.
Hawking says there is no God? Let him come forth and prove it with an experiment. In fact, if Stephen Hawking gets on his feet and claims there isn't a God, alot of us would believe it (since isn't he dead, bur also crippled?) but I'd still demand he make an experiment.
I dislike scientific theorists. It's fun to write books about crackpot theories you have, not so east to make a convincing experiment.