Security means protection from malicious intent, safety means protection from malfunction or accidents. I guess most people don't hire security guards to protect them from accidents. While many people may not see much of a difference, the difference is well defined in the computer world.

That's no reason to make them synonyms, but to write good tag wikis explaining what they are about.

Having a fire exit in a building makes it safer, but less secure. This isn't only an issue for information security.