I made a comment about this on another post that's now unlinkable because the post has been deleted.
I suspect the quote is not just misattributed, but maliciously so, given its sudden appearance with a purportedly anti-Zionist framing, thus associating anti-Zionism with 'extermination'.
While Che never said that, the speech mentioned in the image here is real (though not given at the date mentioned in the image), and it does address colonialism. It even mentions Palestine! You can find the full text of it online.