Is putting processes in separate memory spaces not a security boundary to you? Isolating separate app responsibilities in separate UIDs? Filesystem permission

Is putting processes in separate memory spaces not a security boundary to you? Isolating separate app responsibilities in separate UIDs? Filesystem permission bits? All those are "weaker" boundaries than containers. Do you really claim that these have ZERO security value? That's silly. Of course containers are a security boundary. They have advantages and disadvantages. Treat them as tools and not slogans.