From this article at “Today I found out” dot com:
Today I Found Out the “Hip Hip” in “Hip Hip, Hooray” was once anti-Semitic.
This phrase is thought to have its origins in the middle-age Latin battle-cry “Hieroslyma est perdita’, which means “Jerusalem is fallen” or “Jerusalem is lost”. This was later shortened by Germanic tribes fighting Jews to “Hep Hep Hu-raj”, meaning loosely “Jerusalem is fallen and we are on the way to paradise.” This also found its way into a Hungarian battle cry “Huj Huj Hajrá”, which more or less just meant “faster, faster”. An alternative theory is that it comes from a Germanic shepherds cry or a hunter’s cry “hep hep”, which was used to rally their trained dogs. It is also possible that this shepherds cry was not the origin, but rather itself was from the proposed Germanic battle cry “Hep Hep Huraj”.
Read on.
I wonder if Weezer will re-record and re-release “Islands in the Sun” to say something other than “hip hip” during that one part of the song.