This guy Crowley wasn't some hack bureaucrat running an academic institution filled with mediocrities. He was a law enforcement officer with a sworn duty to uphold the law, and he was responding to a call about a possible burglary in progress.
I have no idea whether or not Gates should have been arrested in this case, but the "constitutional" arguments put forth by Silvergate are misleading.
Cops are government officials too and as big government has grown the dangers of abuse from them have also grown. If you don't believe that the abuse of power by cops is a problem in the U.S., go to youtube and you will see many examples such as the tasing of a 72 year old grandma who was tased for asking too many questions.