Dear modchebp shadchan,
You absolutely did the correct thing.
The yeshiva velt has too many (and even one is too many) boys whose ge’onus in lumdus and yeshivishkeit is surpassed only by their conceit. In my opinion, the learning this boy does is not worth a dime.
You were given the opportunity to let them know that some people were taught the difference between right and wrong, and you did not let it pass. Good for you. And even better for the girl.