Why are you disappointed? It was just a question out of curiosity. Nothing wrong with asking a question, this is a community centered around discussions, is it not? It's not Stack Overflow or something, where we follow a strict question-answer format.
It is hard for people to make transitions specially because they probably used Windows their own life. If they are asking for a FOSS firewall they most likely know they should transition to Linux at some point.
And that is just your assumption. What if they were only using Windows to play some games, but didn't realise that those games were now actually playable in Linux?
... this does not compute. If you actually truly prefer open source, why are you using Windows?