(Formal) Argument and Counter-argument

Honestly the reason that I start this thread is more like a shameless call for help.... Hard to explain, but I will have to participate in a sort of internet-argument~ish session, but have to be in a much more formal format. Means I can't be an ass, have to handle cheap personal attacks in a calm way, while avoid making any (obvious) personal attacks myself. Key is still to win the audiences, but get your opponent acknowledge your points are important too. So need everyone advice on a couple of situations, for example:

If my opponent making an absurd claim that obviously false, but there for underlined implication. Let's just say for example if he/she claimed that. "Those (Asian) guys can't even handle real relationship. No one (or "None of the girls I know") like to date Asian men". In this case obviously the claim simply can't be true. But it was there to imply that one with Asian culture/ ethnicity is inferior when it comes to handling relationship. In that case, what should i do?

1. Ignoring it will feel like I acknowledged such points
2. Personal attacks or witty comment ("your friends must be unable to handle different culture/ a bunch of racists") are too obvious, could reduce the formality of the session. And even if you win, your opponents will hate you anyway
3. Disapproving it with personal experiences (I know these girls in high school who date and marry John who's a Filipino) will feel like I could only name a few exceptional cases
4. Disapprove with official statistics(divorce rate or men at the age of 30-55 being single in Asian community is no higher than other ethnicity), could be called out that it does not relate to the original claim

I know this type of claim will come out at some points and one of the cornerstone for their argument. So I need a way to completely destroy it so they can't continue from there. Any suggestions?

(Formal) Argument and Counter-argument