Let me tell you a true story with some twists to protect identities.
A stereotypical white American from the mainland suburbs travels to Hawai'i thinking she understands everything about how America is far less racist than it used to be and not understanding what her black and immigrant friends were talking about when they disagreed.
She thought she was "down" and wanted to hang out at non-tourist spots on Oahu (IE not Waikiki in Honolulu and not the tourist North Shore section). She travels off to bars where locals hang out. She walks into a bar and conversations stop. People turn and give suspicious looks. She is served but the vibe in the air clearly shows her she is unwanted. She would sit at the bar, used to her blond hair making guys want to buy her free drinks. Instead bartenders at local bars serve customers who arrived at the bar after her ignoring her for as long as humanly possible. Instead of queuing up to buy her free drinks as she is used to, guys move away from her seat at the bar to not be close to her. Servers, male and female, never say more than they have to. Often times servers "forget" to bring her the extras she asked for in her meal always with a "oh sorry I forgot" despite the fact the locals seemed to be getting excellent. This continues consistently for several days in a row.
No one directly calls her a Haole. No one actively refuses her service. No one ever does anything that would fit a US Republicans subjective (because no dictionary can actually define racism).
Yet she cancels her trip weeks early and returns home because she is made in very subtle and sometimes indescribable ways to feel unwanted. She calls her black and immigrant friends and says "I finally understand what you all mean when you say the vibe of racism that I never noticed before because I was immune to it. Now I understand because I have experienced it."
Now, you might tell her she never actually experienced racism because the story doesn't fit whatever arbitrary definition exists. But she knows what she experienced and how it felt. And it exists. I have a feeling other black and minority posters on her know exactly what I mean when I tell this story.
---
Oh and just so this is not only anecdotes I suggest the great work of Devah Pager who showed another type of subtle racism. Being a black person with no criminal record is worse than being a white American with a criminal record regarding job prospects
"In fact, even whites with criminal records received more favorable treatment (17%) than blacks without criminal records (14%).34 The rank ordering of groups in this graph is painfully revealing of employer preferences: race continues to play a dominant role in shaping employment opportunities, equal to or greater than the impact of a criminal record."
https://scholar.harvard.edu/files/pager/files/pager_ajs.pdf