'This Is Why I Took a Knee'

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Bruce Maxwell -- the only MLB player to kneel during the national anthem -- went off on cops during his Oct. 2017 arrest ... telling police he took a knee to protest "y'all motherf*ckers."

As we previously reported, Maxwell was arrested for aggravated assault at his AZ home after allegedly pulling a gun on a Postmates driver.

When cops arrived, Maxwell -- not wearing a shirt -- began berating the police officers.

"Think I'm intimidated? Cool. Cool. I hope so. I’m not afraid of f*cking none of y’all n*ggas. I don’t give a f*ck."

He continued, "Guess what, f*cking half of America afraid of y’all motherf*ckers. Yeah, that’s the reason why I took a knee. F*cking anthem, dog."

"F*cking our country is afraid of the f*cking police. Wanna know why? Because the f*cking police does unjustice sh*t and gets f*cking paid leave for it."

Maxwell explained he's mixed race -- "My mom is white as sh*t. My dad is black as a motherf*cker."

Later in the video, Maxwell gets emotional as he tells cops he and his family received death threats for his national anthem protest.

For their part, cops say Maxwell reeked of booze. He was transported to a nearby jail.