In the post-Oct 7 context, most likely, and if we're to be charitable here (and absent any other signals to the contrary) what they meant with those symbols was some mixture of "Our people are under attack, we need to stick together" and "Bring the hostages home, please."

Your misconstrual of the yellow ribbon, which obviously has deep grassroots origins (and in the current context only refers to the wish for a speedy return of the hostages) as being somehow suspect simply because it is also worn by government officials -- seems especially inappropriate, in this context.

And it certainly is not appropriate for you to tell them that they should be using the Star of David or other religious symbols, which have entirely personal meaning to them, in their stead.

What matters here is that there's no way these people deserve, or even remotely deserve, to be assuaged with antisemitic abuse (for the sake of simplicity, let's just assume that's what these replies actually were) from anyone. Even if some of these people were also indicating (via the Israeli flag or other means) some degree of support for their government's policies.

That's the main point, and the only point really, to be drawn from these observations of antisemitic abuse (assuming they are accurate).

BTW this applies to pretty much any national flag, in any context. One can think whatever one wants to about it, privately. But there's no reason the person displaying it should be subjected to comments of any kind (particularly comments directed at their identity) simply for displaying it.

It's just one of those things we need to cut people slack for.