Broadly, some definitions posit that racism is a prejudiced or discriminatory attitude against members of a certain racial group, while others stipulate that such attitudes need to be accompanied by race-based structural or institutional inequalities in order to qualify as racism.
I tend to lean toward the former definition for reasons whose details bear no relevance to this thread, but based on that definition, have you ever been a target of anti-white racism? If so, how often, and in what context or contexts?
I don't know if I would define it as racism in the strictest sense, although I have found myself in places and situations where white faces were kind of rare. I can't say that I've experienced any overt hostility, but I could tell in some situations where people were kind of wondering what I was doing there.
There was a time when I was working as a substitute teacher in some pretty rough schools in California, where whites were a very small minority. But it really isn't like what movies or TV shows or even the news media would portray it as. Individual mileage may vary.
My mom told me that she once entered a shopping mall in south central L.A., and she saw some young black men giving her dirty looks and looking very hostile towards her, so she made a hasty retreat. That may be an indication of hostility towards whites, although whether it qualifies as racism may not necessarily be relevant. Even if one were to argue that, due to the absence of "race-based structural or institutional inequalities" it would not qualify as racism, it doesn't make such attitudes any less hostile or harmful.
Here's one I remember from working at a school on Cinco De Mayo many years ago. It was a high school, about 50% Hispanic, 30% black, and the remainder were mainly Asians and whites. As there had been violence in the past, particularly between black and Hispanic students, the school decided to turn it into a kind of multicultural awareness day, so that all cultures represented at the school could celebrate their culture and share in the diversity. It started off kind of nice. Some kids were setting up some booths with a diverse variety of foods from different countries. There were some Samoan-Americans who were preparing to perform a dancing ceremony from their culture. The Hispanic students put on a performance in the gym with Mexican folk dances and songs, with some of the black students in the audience behaving...less than politely. Not all of them, but there were just enough boneheads catcalling and heckling that it kind of soured the presentation. Afterwards, it was time for the black students to have their cultural performance, and just as they were getting started, many of the Hispanic students marched out of the gym, walking right through the blacks' performance, pushing people and making it clear that they were angry.
That's when all hell broke loose. It soon turned into a campus-wide riot, mainly between black and Hispanic students. The white and Asian students and most of the faculty just hid in locked-down classrooms and let the police handle things. It took more than 100 cops to restore order, but what a mess.
I don't know if an incident like that could be called racist, depending on how it's defined. But it was certainly bad, even if it's not specifically called racist. I think a lot of people might get a bit too overly attached to labels, and I've noticed a lot of handwringing over what to call things - as if that's somehow more important than what's actually going on.