What is the most secure GNU/Linux distro?

Just take a photo of your screen

Trick question. None of them.

You think they're all exactly equally secure?

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[Obligatory Gentoo shilling]

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backtrack. the quieter you become, the more you are able to here

I suppose gentoo hardened or alpine. If you are looking for BSD's HardenedBSD, OpenBSD is a meme.
I'll be using gentoo hardened.

pentesting distros aren't secure.