The article doesn't say anything about Clinton or Obama so where is your information source to back up the claim that Obama or Clinton had a hand in this?

Did you even read the article? I suspect NOT... If you had you would have found this:

That's because the Supreme Court has ruled that speakers can't be made to pay the costs for whatever hostile audience may appear, just like a university can't ban a speaker in anticipation of protesters.

"Speech cannot be financially burdened, any more than it can be punished or banned, simply because it might offend a hostile mob," Justice Harry Blackmun wrote in 1992.

Spencer paid $10,000 to rent the hall and provided security
inside.

Here is what Rick Scott did fearing the worst:
Ahead of Richard Spencer speech, Florida governor declares emergency

He is the one that cost the taxpayers money!