Usually they say... "We are the Borg. We will assimilate your biological and technological distinctiveness. Your culture will adapt to serve us. Resistance is futile."
In the case of undesirable races like the kazon, the only true comment above is "We are the Borg" the rest of that mantra is inapplicable to the Kazon... Because the Borg are just not into them.
If they're also not worth the cost of a torpedo, could this be the basis for a friendly relationship between the Borg and the Kazon?
Or would the Borg still try to keep some distance "We are the Borg. Go away. Please. Just leave us alone. You're boring and you smell. Buggering off would be appreciated. Now. Why won't you just leave us alone?"
Have you ever seen The Cable Guy?