Because Obama didn't go out of his way to put himself in the news every single day the way Man/baby T does. Obama was presidential, graceful in public, and diplomatic with the Press. He didn't foolishly attack large swaths of the country and his own government.
Trump has attacked the Press, his own Intelligence Community, the GOP, and even the military. He's also attacked women, any citizen who doesn't support him, immigrants and disabled people. He deserves every arrow hurled his way. Hopefully one will eventually find its mark.