There is no such thing as racisim against white people (or, if there is, it's very rare), only race predjudiced. Racism is defined as one race is superior against all others, IE- White supremacy. The word "Racism" is often used too frequently in contexts where "predjudiced" should replace it.
Unless of course they were going on about how white people are filthy and inferior to say, asians. Then yes, that would be "White Racism".
/EndEnglishnerdrant
For the record, I am not saying that what you witnessed was not offensive or hurtful, just that the people on Wikipedia may be using a different definition of the word. Even so, if they were being predjudiced towards "race" it should be edited because Wikipedia is supposed to be an unbiased source.