Maybe to sell more anti-viral software.

That’s the only explanation I can give for Enrique Salem’s performance in a video posted on CNNMoney Thursday entitled “Macs are no safer than PCs.” (Video below the fold.)

Fortune‘s Adam Lashinsky asked Symantec’s (SYMC) CEO several different ways whether a Mac was as likely to get attacked by malware as a PC.

That’s not a hard question, and it can be easily disposed of statistically.

Sophos Labs’ Richard Wang, for example, told eWeek last fall that his guys see one or two attacks on Macs each week, compared with tens of thousands per day against Windows PCs. That ratio is a good deal smaller than the two operating systems’ relative market shares.

It’s true that Microsoft (MSFT) took pains to make Windows 7 considerably more secure at the design level than earlier versions — even more secure, many experts believe, than Apple’s (AAPL) OS X. That won’t help the nearly 9 out of 10 Windows users who are still running Vista or XP, the malware writers’ favorite target.

But if you’re a Mac user and Enrique Salem has managed to scare you, I’m sure he would be happy to sell you some Norton AntiVirus protection, just in case.

Below: Lashinsky’s interview.

[cnnmoney-video vid=/video/technology/2011/02/16/ctd_symantec_windows_apple.fortune]

Also on Fortune.com:

• Why are there no Mac viruses?
• About those gangs of Russian hackers targeting Macs
• Jailbroken iPhones infected, again

[Follow Philip Elmer-DeWitt on Twitter @philiped]