I assume hardly anyone remembered, or payed much mind, to the origin of that word by the 1920s. I don't know who coined 'homophobia' or 'feminism' or many other concepts; they're just common words we use.
And I would complain about the false accusation if that was the case. As it stands "antisemitism" is what's being used to label people who oppose Zionism. It's just like how "communism" was used during McCarthyism.
I think the accusations are sometimes unfair, and other times accurate. I wouldn't like for the world just to dismiss hatred towards Jews, or any other group, out-of-hand. More than anything, I would like to see measured and humane discussion in the media about the Middle East; but sadly I don't expect that will happen.
The amount of unfair accusations dwarfs any real ones. For instance many in the VC world have accused Paul Graham of being antisemitic for simply showing concern about Palestinians. To be clear no critique of Israel including that you don't think it has a right to exist is "antisemitic". Israel is a state not an ethnicity and it was formed under what most consider to be illegal and unethical circumstances and it grew through ethnic cleansing. It's official religion is of no consequence when judging its actions.
One way to address that is to become cynical about 'antisemitism', but I hope that doesn't become prevalent. We've already entered an era in which majority groups resent minority grievances. Seems like that could lead to a lot of backwardness.
I alluded to this already, but it's so rare to hear public figures discuss Israel/Palestine without distorting and filtering what they say to promote one or the other side, it makes resolving things impossible.