Please don't show hackers with masks. People without knowing much about the subject will really think they are some kind of criminals wearing this masks. I never saw any hacker at a conference wearning one of these ;)

The statement with the free software is absolutely right. Security through obscurity had been proofen wrong in the past many times and just people without knowing anything about the security aspects will claim that it is better to have the code to hack a system. Most system hacked are reengineered, so it doesn't help you anyhow.

When looking at the recent hacks, the meltdown spectre for example, average joe linux user does already have fixed in their kernels while media still reports it. Having a non-homogenious system with a well infrastructure does help to fix issues very fast once they had been identified.