This is not only about terror activity.
I'm an Israeli, politically left leaning and it's a shame that I need to write the following(and for many years I've believed the opposite) :
The Israeli Arabs are a big problem. We've seen it during the last war with Gaza, when those many Israeli Arab citizens created mobs that did many violent actions in quite a few places. Israeli people in some cities had to flee their homes. And yes there we're also Israeli mobs.
This is not the first time this happens.
It's gotten seriously bad, so bad that now the Israeli Army is building special roads bypassing areas with a lot of Israeli Arab citizens, because those areas aren't safe to use in the case of a war on our borders,
So objectively, Arabs and Jews mix very poorly.
So is it wise to add another 130K such citizens every ten years ? Or more specifically, Palestinians, who hate us even more ? Or is it just increasing the problem ?
And sure, this isn't a nice decision. We Israelis live in a partial war situation. That's the reality.
So you can't compare it to barring Mexicans from enter to the US. It's much more complicated.