Right.
All Mac users run "security" because OS X has built-in security, including malware prevention, malicious code execution prevention systems, selective privilege escalation and the software firewall. Just like Windows. I always tell new Mac users to enable the software firewall the first time they start their machines even if they're behind a hardware firewall and in no way am I "proud" of the fact that the software firewall is disabled by default.
Do most users need to run a resident anti-virus? No. For some it may be of benefit, as Terpfen explained earlier. For most, it is no less pointless than running an anti-virus in UNIX/Linux.
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