I don't think it's racist....but I'm definitely interested in why you believe it is.
Israel announced plans to annex parts of the West Bank. Let's say that I'm interested in finding out what Israeli Jews think about these plans...so I set up a survey asking them what they think about the annexation plans.
If I don't express that I only want Israeli jews to answer the survey....there's a good chance that Palestinians and other Arabs will answer.
If that happens....I won't find out what the Israeli Jews think about the annexation plans, which was the whole point of the survey.
Surveys and polls do this sort of thing all the time.
To be clear, I said that your poll is racist
in it's premise. So is any poll that breaks down opinion demographically according to race. You may not think it is, along with others, and I can understand why that is.
But please consider, "Race" generally refers to physical characteristics people share in common, while ethnicity is more about language, culture, country of origin. In times past "Race" used to mean speaking a different language believe it or not, but that became problematic since for example, the "Human race" speaks different languages. The term race is therefore an unstable term without some substantial qualification. Wherefore the Supreme court ruled that race should not be used as a demographic to classify people, because it is racist in it's premise as if people who all share a dark skin represent the same cultural view.
The example of a poll concerning what Israeli Jews think would be based on ethnicity not race. Since your poll is about racism, it makes sense to me that you would want to know what white people think, but it's still racist because it assumes white people would see things differently than black people based on the color of their skin. The term racism is therefore unstable in it's definition because the term race is unstable.
Some people disagree about the definition of racism. Some people believe that only white people are racist. The first two options address this belief....the third is for those who disagree.
I thought it was rather clear. We all occasionally prejudge others based upon race, whether consciously or unconsciously.
There is a problem with the poll precisely because people disagree with what racism means and how to qualify the negative aspect of racism. It's therefore not clear that the third choice is for people who disagree that only white people are racist, (implying black people are too). It depends on how one defines race, racist and racism, and how they qualify the negative aspect of it.
For example when the issue is seen in the negative as an ongoing struggle for equality traced back to Americas history of slavery based on racism, then of course under those circumstances, people would count racism as being a problem only white people would have, that wasn't a problem for blacks since it was black people who were slaves. Others might even portray it as a problem for blacks because they were the slaves.
This summation of it being traced back to slavery however is not necessarily at odds with the caveat that not all white people were for slavery, only that black people certainly were not for slavery because they were the slaves. And it's not qualified as to whether blacks or some blacks would be for slavery if they were the masters. Are we talking about the wrongs of racism or the wrongs of slavery/subjugation
no matter what color? Notice if I had said
no matter what "race", it would automatically suggest to the mind that race is not about physical appearance but about ethnicity. Wherefore I chose the word "color".
You then might say that these people could choose the option of some white people are racist, but there is no qualification in that answer indicating that black people could be just as susceptible to racism. You complicate this further by indicating in your OP that you believe that BLM is all about blaming whites for being white, while specifically saying the poll is to be understood as about racism against blacks, not against whites.
My point is that this is all lost in semantics, and much of what we are debating is created by semantical confusion which then leads to misunderstanding. Sorry for the long post.
And for those Christian claimants who refuse to recognize equality with fellow Christians in Christ, we also have an eternal fire. 
