The argument "Free to search else where" is no longer valid for Google. This was a valid argument when Yahoo was the Dominant Search Engine and Google was still a private company.
US Law allows intervention when a company or a couple of companies hold monopolistic power in that industry.
A company can set their own price if it is part of a free market competition. If you don't like their price then go buy else where. This is valid. However, when a company have monopolistic power then they don't get set the price without government regulation.
Netscape browser was a popular browser at one point. Microsoft has monopolistic power to eliminate Netscape by:
1) Microsoft offered their browser for Free. This eliminated a paid application model for Netscape. How can they compete with Free? Microsoft can generate losses for years on that product line to put Netscape out of business.
2) The operating system automatically use Internet Explorer by default without giving the user an option to choose their browser
3) The operating system was made incompatible with Netscape causing it to crash and steering users to use Internet Explorer instead.
In summary, Google might behave like small startup tech company but they have monopoly power.