Definitely no! Never tried black semen but I know white guys taste different from one guy to another! I think the post above is correct, it all depends on their diets! One guy who was a diabetic tasted really sweet to me!!
Diet is the main factor in semen taste. My wife commented on several occasions that when I traveled on business my semen tasted different when I got back, especially if I was gone more than a week and more so if I went to Asia.