As Zahavasdad pointed out, the orchestral piece of Here Comes the Bride was written by Wagner sr”y and not Mendelssohn. Until today, the Israel symphony orchestras (with rare and very controversial exceptions) refuse to play Wagner’s music. According to the historian Jacob Katz, Wagner had a tangible influence on the advance of Antisemitism in Eastern Europe in the 19th century, and was an important philosophical (sic) influence in the rise of Nazism. I am an avid classical music lover, and I will not listen to Wagner.
As far as Mendelssohn’s descendants are concerned, it would be wise for some of the above commenters to leave it alone. If the moderators would allow it (they won’t) , I can easily comprise a long list of gedolei hador from the last thousand plus years whose descendants left the Jewish and/or Torah world. This is a glass house, and the dwellers would be wise not to throw stones.