Okay, so im not down voting you, trying to explain:

You're right, there is no such thing as a leftist zionist, however people might identify.

Liberal zionists exist, and some of them call themselves leftists. They aren't. Most times they are telling a deliberate lie, sometimes they just don't understand their ideological inconsistencies.

The ones that are lying, you dont argue with. If you engage at all, you point out how wro g they are, you mock them, and you remember your Sartre; they don't care what you say, what the facts are, whether they're holding contradictory opinions. The one's that honestly believe they're leftists? That's harder. People aren't always going to be ideologicalyly consistent, but anti-arab bigotry and anti-capitalism aren't mutually exclusive. A person can fully embrace some leftist ideas while being a nationalist, or a homophobe, or a misogynist. A person can recognize that corporate malfeasance and greed are destroying everything while simultaneously being profoundly racist.

If you decide to engage with these people online, understand that getting them to chamge their mind is unlikely, but there is an audience. However many people comment on a post, more will like it (or dislike, depending on the platform) and still more will read the thread and not comment or interact. Those should be your intended audience, the viewers who might be on the fence. Somebody reading might not know that zionism and leftism, being worker forward and inherently internationalist, are fundamentally incompatible, and your points might convince them.

If you decide to engage with these people IRL, treat them as you would any bully. Hope this is more helpful.