Suppose we can clear this up a little bit. People are most definitely not hating on makie whatsoever. Everyone loves him as falcon, he was fantastic, a great actor and played that role amazingly. But there lies the problem, you've killed 1 character off and made him into captain America and it just doesn't fit to most people. 
Bucky obviously would have made the best choice for me personally and I would still have loved to see makie as falcon, so no this isn't a race thing whatsoever, he just had a solid character and they got rid of it in order to shoehorn this in.
Also on another point why this movie will flop is the fact they have had to re shoot this movie 3 times already as the test screenings were absolutely piss poor.