Amazon founder and CEO Jeff Bezos defended the “Black lives matter” message posted on the commerce giant’s site, explaining to an offended customer that the message “speaks to racism and the disproportionate risk that Black people face in our law enforcement and justice system.”

“‘Black lives matter’ doesn’t mean other lives don’t matter,” Bezos told the customer in an email exchange posted to his Instagram account Friday afternoon and spread on Amazon’s social media channels. The world’s richest person added, “I have a 20-year-old son, and I simply don’t worry that he might be choked to death while being detained one day. It’s not something I worry about. Black parents can’t say the same.”

Amazon, like other corporations, released statements in support of the widespread uprisings against systemic racism and also announced $10 million in donations to social justice organizations earlier this week. A banner atop the company’s shopping site proclaims “Black lives matter” and points to a corporate blog post about the donations.

That message was “quite disturbing” to an Amazon shopper, Macy, who emailed Bezos. The customer, whose surname was obscured in Bezos’ post, wrote “I am for everyone voicing their opinions and standing up for what you believe in, but for your company to blast this on your website is very offensive to me and I’m sure you’ll be hearing from others. ALL LIVES MATTER!”

Bezos disagreed. “None of this is intended to dismiss or minimize the very real worries you or anyone else might have in their own life, but I want you to know I support this movement that we see happening all around us, and my stance won’t change,” he wrote.

Race: a reckoning in Seattle and across U.S.