To an extent, this is a valid concern.
Partners in Torah warns their Torah Mates not to discuss politics because you can only lose.
(1)If you disagree you can alienate a passionate supporter of the opposite side of you (2)waste energy on politics rather than Torah (3)some of these people’s current religion is liberalism. Their whole value for Torah is largely only to the degree that they believe it supports liberalism. They believe in liberalism with such a religious fervor that if told it conflicts with Torah they won’t accept Torah.
OTOH when it comes to Zionism I’m not sure this is such a big concern because the younger generation anti-Zionist crowd would not be receptive to Kiruv either way. They don’t identify with Judaism as a religion in any way. Their anti-Zionism seems more motivated by an effort to fight and deny their Jewish heritage and assimilate than a principled understanding of the issue. (It is also motivated to fight the emptiness they have in their lives by rallying around self-righteous self-aggrandizing causes like being anti-Israel)
They would never agree to sign up for Partners In Torah to being with. They aren’t coming for a Shabbos meal either way. Or if they are only to make fun when they leave.
So Zionism won’t make a difference either way to them. Can you imagine doing kiruv on a guy like Bernie Sanders?
That it is who you dealing with today