The Philadelphia Union defender is hopeful that football's fight against racial inequalities can lead to change in the world.
"I was called the N-word at a youth game," McKenzie told Sky Sports. "I've had racist chants at me in games. We see this happening around the world.
"I've experienced it and this is the story of many players -- whether you have my skin complexion or a lighter skin complexion -- you are placed into a bubble where you have a target on your back because of your skin colour.
"Hopefully, the powers are listening. It's made me think about how we got here. Made me think about, in my 21 years, how many black lives have been taken with justice not really following.
"For me when I step outside of the lines and take off my jersey, I'm driving home and I'm seen as another black man -- that's the point."
There have been a number of race-related controversies in Major League Soccer this year. Real Salt Lake owner Dell Loy Hansen was found to have made racist comments to team employees and has since announced he will sell the team.
Supporters of FC Dallas booed players for taking a knee back on Aug. 12 and when then-Dallas defender Reggie Cannon called the response "disgusting," he received death threats. Cannon later stated that the club asked him to apologise to fans for his remarks, which he said he refused to do.
There have also been incidents across Europe where the Champions League clash between Paris Saint-Germain and Istanbul Basaksehir was suspended after both teams walked off after an alleged racist comment from the fourth official.
In the United Kingdom, Millwall fans were condemned after they booed their team and Queens Park Rangers for taking the knee before a match.
However, McKenzie said that he is proud to take the knee and also confirmed that he would be willing to leave the field if he was subjected to racism.
"It's huge for me [to take the knee]," the 21-year-old added. "This is an issue that we've been plagued with a lot longer than just this year.
"This issue of racism -- systemic racism -- that has plagued us for centuries. It's evident to see that we are now in an era the idea of racism has shifted into a modern day issue, where it might not be blatant or explicit, but may be implicit. That's something that's really hit home for me."
He added: "Yeah I would [walk off the pitch]. I'd have to really get to the bottom of what happened first. Football is international and things can get lost in translation.
"That's why I'm learning Spanish and other languages to make sure I can get to know people without there being too much blur."
This year has also seen the formation of the Black Players for Change (BPC) -- an organisation made up of more than 170 players, coaches and staff in MLS to fight against racism. Last week, the BPC was named as the 2020 MLS WORKS Humanitarian of the Year.