1000s of factors come into consideration. Also the time a person grew up, or the country, and so many others too.
But I'd say a person who experiences the prejudice and difficulties related to being handicapped, will understand the issues better, and hopefully be more empathetic. But yes, I was talking here about a specific form of racism, aimed at a sepcific group. They will understand those specificities better than others- and will also be more empathetic, or at least understanding, of racism in general or aimed at other specific groups.
Personally, being handicapped for a few years will have given me an insight of what it feels like- and I've never forgotten. And because close friends and direct family have experienced racism very directly- and in our family, the darker the mixed race, the more virulent the racism and barriers put across in front of them - I am perhaps more aware and empathetic. NO virtue signalling here, for sure, just personal experience. And for sure, those friends and relatives' experiences- obvioulsy carry tons more weight than mine.