Because an opinion can’t rise to homicide, even if it influences policy. That’s not what homicide is. Instead, it’s simply bad policy, to be punished at the ballot box.
This is a broken system. When somebody allegedly steals a backpack they get thrown in Riker's. When somebody with substantial power causes a whole bunch of people to die in aggregate via pollution, misinformation, or whatever our society has no mechanism to punish them.
If your policy of letting kindergarteners play with grenades goes bad, you go to jail.