The difference is this from the the article to which you linked: 

"There is no evidence in any of the public records that the FBI believed that the Clintons or anyone close to them did anything illegal." 

The FBI investigated, and that was the conclusion. On the other hand Trump is still under investigation thus there are no conclusions as of yet. 

If Trump had kept his fingers still and mouth shut, his investigation may have let to the same conclusion. Instead, he denied that Russians even tried to influence the election, he fired Comey for the stated purpose of making the "Russia thing go away" etc. 

It's clear that Trump has something to hide but unlike the Clintons who may also have had something to hide, he went on the attack and drew further attention to himself and his dealings. The Russians may not have done more than what they did with the Clintons but Trump lacks the emotional and intellectual development to remain disciplined. He is just giving Muller ammo.