I honestly love this retort. It is such a great one. If you think that OSX or whatever they are on now is an optimal operating system you are kidding yourself. It still runs on UNIX, just like Linux and they both have their vulnerabilities.
Fact is kid, the usability is the same. You can do things on a Windows you can't on a Mac, and vice versa. Additionally, you can dual boot so that you have OSX and Windows on one computer if you so choose due to the compatibilities of the Intel chipset nowadays.
Moreover, OSX is NOT more secure than Windows, this is a downright lie. It is less ATTACKED as has been said previously. It is actually far less secure. Give it a few years, when people start to actually care about Mac's and Mac users, you will find your plethora of viruses, spyware and malware around every corner and it will take Mac years to catch up.