do my mac devices needs antivirus protection? i just had an ichat with apple and they said that I don't need to buy protection.

My Schwab account was recently frozen and when I contacted Schwab, they told me that someone in Los Angeles attempted to access my account. I initially thought this was Phishing, but my account was frozen. The Rep at Schwab said to make sure that all of the devices I use to access the account should be cleaned and be running antivirus protection. I had an ichat session with apple and they said I don't need any. My brother is now reading articles from Fortune magazine saying that we do need them. Help?!