Like who? I can't think of any who were as outspoken as Wagner.
Frankly, the history of German literature from the Enlightenment to the fall of the Third Reich is a despicable catalog of anti-Jewish sentiment. Sympathizers were rare. In varying degrees both major and minor figures expressed hostility to or contempt for the Jews: The Grimm Brothers, Hegel, Schopenhauer, Karl Marx, and even Martin Luther who railed against the Jews and proposed the burning of their synagogues. Franz Liszt was another composer who was not inhibited in his expressions of anti-Semitism. In a publication of 1881, The Gypsy in Music, he termed the Jews "sullen, servile, cruel and avaricious."
The reality is that in countless ways he was an entirely characteristic symptom of his age, reflecting it's outlook, its prejudices and its neuroses. This in no way excuses his words, and I do not forgive him for them because of my appreciation of his music. Besides, the person he ended up hurting more than anyone else was himself and his legacy. However, his anti-Semitism is totally unimportant for an understanding and appreciation of his art.
Nevertheless, it is indeed important for an understanding of the man. It was a significant expression of his emotional make-up. And I think the more you learn about the sources of his particular brand of anti-Semitism, the less scary it becomes, and the less connected to the anti-Semitic movement of the 1870s and eventually to the attitudes of the Nazis it appears. Saying he would have been a part of the Nazi movement if he were around 50 years after his death is not only pure unfounded speculation, but doesn't add up with the facts of his life. Wagner's anti-Semitic attitude, writings, and comments did not appear until his late 30s. This was not some deep embedded prejudice from his youth. It seems that to Wagner his connection with the successful Jewish opera composer Giacomo Meyerbeer brought the misfortune that many people, friends included, had received the impression that he had something in common with Meyerbeer artistically. That notion had brought Wagner to despair and caused him to demonstrate publicly his distance from his former patron. His negative opinion of Meyerbeer was formed independently of his being a Jew, but he then used that fact to base his attack and argument against Meyerbeer's art. The artistic inferiority of Meyerbeer was not just an opinion, but a fact, because it was the product of a member of an inferior race. So see, Wagner used the common anti-Semitic outlooks and speech of the time as the stick to beat Meyerbeer with. But after his infamous essay was published, it had the effect of creating a sort of paranoia in Wagner himself. He used it to explain any setbacks and failures he had in his life, and to explain harsh comments and reviews by members of the press. He started to believe it was their way at getting back at him for publishing his essay. Behind every obstacle, he truly believed was a Jew in hiding. And soon his outlook became that any opponent of his was a Jew.
Yet while he now had complete contempt for Jews as an abstract concept, he never became anything close to a Nazi. When the representatives of the anti-Semitic movement that arose in the 1870s came in hopes that they could claim Wagner as a famous herald of their doctrine, and asked him to sign a petition to the Reichstag protesting the recent grant of full rights of citizenship to Jews, twice he refused explaining that such actions were not really his style, that he preferred to just write, and to leave such mundane things to others. Never did he refuse the help or friendship of anyone because he or she was a Jew, or on any other racial or religious ground. He judged all individuals by their artistic talent and/or their understanding of himself and his aims. He was often surrounded by Jews aiding him in completing and staging his works, much to the consternation of others with a more practical hatred of Jews. That his name was later used as a central symbol of the anti-Jewish movement is no surprise, and a consequence of his writings. Again, his legacy suffers most of all from it. But to burden him with the actions of others is going too far.