The hard part is getting past existing presuppositions.
Maybe a good way to go about it would be to imagine a hypothetical situation in which there wasn't any government, but there WAS societal problems which needed money. Maybe to help the poor. Something that the people in your audience will support in principal. Then, you could ask your audience "how would we raise the money"?
After going over a couple of fundraising techniques - selling cookies, asking for donations, etc..., imagine a hypothetical person to suggests taxation (don't call it taxation - just describe it).
"Hey, I got an idea.", the man would say, "Oh, this is so good - we just go around and tell everybody that they HAVE to give us money".
"What if the people refuse to give you the money?", the rest of the people would ask.
"That's easy!", the man would say "...just tie them up, throw them in your car, bring them to a building surrounded by armed guards, and lock them in cage. After you do this a few times, the rest of the people will get the message and give you money without much fuss.".
"GREAT IDEA!", everyone says. "That would definately work, but it's that like stealing?"
"NO, because it's going to help poor people. That money will be used for good purposes. Sure, TECHNICALLY it's stealing, but we just won't CALL IT stealing. We'll just call something else- something official-sounding. How about "taxation"?"
...Something like that could be used as a rhetorical device. You may need to be a little creative, obviously, but I think that's a good method of getting past the reactionary response.