A big business is more liable then a small business, they have more assets to lose, assuming they lose a copyright infringement case. Lawyers like to sue people with money.
Big business historically have been the target of GPL lawsuits.
So I don't buy your theory.
GPL is a probably the best open source license for distributing software you actually want to make money from. What you do is charge a fee for people who don't agree to the GPL terms. With BSD, it's not quite as easy to do this. Notice some of the most profitable open source products (eg: SugarCRM, and MySQL) are GPL.