"I always was under the impression that Antisemitism is when someone is against Jews because they’re Jews, basically like racism but against specifically Jews. But lately I see the word Antisemitism used very lightly ". What else was that supposed to mean?

But lately I see the word Antisemitism used very lightly basically if someone is dissatisfied with the actions of the state Israel then they are called Antisemitic.

Not OP but: I mean if you bothered to read the sentence you quoted to the end you'd have your question answered

It means that now you can't criticise Israel actions without being called an antisemite, even tho you don't care about them being jews.