"It should explore potential habitats on Mars like the Southern Highlands, where life could persist in salt rocks close to the surface" is basically saying that we should throw away planetary protection guidelines in favor of studying places with potential for extant life, an argument that the author has been making repeatedly for a long time, and what the article I linked counters.

The discussion about Viking lander results was just build-up for that final paragraph making the argument for new life-searching mission.