[Edit: Thank you to OP for sharing, and my heart goes out for your exp]
Actually, the 14th Amendment (where the "equal protection" clause is) applies specifically to the states:
"...nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."[1]
The 14th Amendment is applied to the federal government via a process called "reverse incorporation":
"Whereas incorporation applies the Bill of Rights to the states though the Due Process Clause of the Fourteenth Amendment, in reverse incorporation, the Equal Protection Clause of the Fourteenth Amendment has been held to apply to the federal government through the Due Process Clause located in the Fifth Amendment."[2]
[1] https://en.wikipedia.org/wiki/Fourteenth_Amendment_to_the_Un...
[2] https://en.wikipedia.org/wiki/Incorporation_of_the_bill_of_r...
Or maybe just make up a story that you swung at them and then kick the crap out of you?
This would solve a lot of problems for both police and civilians: http://www.nytimes.com/2013/04/07/business/wearable-video-ca...
With violations the officer has 100% discretion about what to do. They can decide not to write a ticket/arrest someone for any reason. This officer was obviously a bad officer that is on a power trip but the OP has not much recourse for what was done. It is sad. I guess it could have been worse. The officer could have made up just about anything and made it worse (like saying you swung at them or threatened them)