The problem is that the tone makes it hard to understand the actual issue being discussed. If someone said e.g. "I think the Dutch government is run by people who unconditionally support Israel", I might respond by pointing out various actions they've taken to oppose Israeli interests. If someone says the Dutch government is "occupied by Zionists", I just don't know what they mean by that, because I've only ever heard the antisemitic meaning of this phrase.
If someone then refuses to explain what non-antisemitic thought they meant to express, I do start to have some questions.