why some people should avoid trying to debate

I realize not everyone agrees on the whole vaccination issue but typically, when they decide to debate it, at least on this site, they bring some good supportive facts for whatever side of the argument they're on.
Well, last night in my English class we were debating (which we do all of the time - love it!) homeschooling.
We were going over reasons why people choose to do it and some kid goes "well most people homeschool because they don't get their kids vaccinated because they don't want their kids to be autistic so uhh they have to"
i said, "In the state of california, and in most other states, that is not true. there are exemption forms" (i didn't even touch on the other things)
He then looks at me and goes "well i don't think so but if they did go to school they'd get polio or something sooo that's why most people homeschool."
wtfff?
i composed myself and simply said, "that's highly debatable".

This person was sooo uninformed on so many different subjects - i couldn't believe he had the nerve to open his mouth.
Later on he also shared with us that he believed the US should do away w/ welfare  

gahh i wish the whole world was like gaga. bring me a real debate, dumbasses  

I hear a lot of dumbshit IRL too (even in my mommy groups!) - its not even worth debating with some people. Why you would decide NOT to be knowledgable is beyond me!

Wow
He should join the debate team 

lol
this is from the kid who sits in the front of the class myspacing and chatting on aim on his laptop all class  

Wow, that guy sounds like a complete moron.

We have numerous types of exemptions for our state including philosophical.

LOL, I'm choosing to home schol because I can teach my child the shit they leave out in schools, I was never happy being in school, neither was my husband, and both of us are 100% commited to teaching, it has nothing to do with us not getting him vaccinated XD
You should have told him to do hisresearch before he opens his mouth and inserts his foot.

I have actually been thinking a lot about homeschooling... doubt it would be an option for me since I am a single mom and need to work though.   I am going to look into it more in the near future!