Never had anti-white racism it happen to me, never seen it happen to anyone else. My mother insists she's been discriminated against because she's Hispanic (that's Latino if you live on the East Coast of the United States), but I'm white as a Saltine, so I haven't gotten any of that myself.
I think nobody takes anti-white racism seriously because of the following misconception (Or is it a misconception?):
It doesn't matter if white people get discriminated against, because white people are already in control of everything. White people have most of the top jobs, most of the top government positions, most of the law-enforcement and military positions, and most of the world's wealth. Other races don't usually occupy positions of power and influence. Therefore, when an individual of a non-white race discriminates against a white person, although it may cause some very serious problems for that one white individual, it's not a big deal in the grand scheme of things because other races can't really do anything to make life bad for white people in general. In other words, anti-white discrimination, on the national and international level, has no teeth. It's a joke.
By contrast, if a white person is able to discriminate against a member of another race and get away with it, then it's a HUGE problem beacause it indicates one of two things.
A. That there's an area/state/demographic of white people (or just an individual white person) that still thinks it's okay to discriminate against other races and is in desperate need of reeducation.
or
B. That we're in danger of letting the last 200-odd years of civil rights gains slip down the tube, and if we don't put a stop to this white person's behavior right this fucking SECOND then it'll just keep getting worse and worse until whitey's got all the other races back on the plantation, picking cotton in the summer heat.
The long and the short of it is that white people have a very, VERY bad track record of racism and discrimination, and, in general, are in a better position to harm other races, at large, with said racism. Therefore, whites being racist is a much more serious problem than anti-white racism.