Agreed, the clear was very clear for me too. I wonder what the microbe eats, and if we can supply that in enough volumes to make a dent to Mars' atmosphere.

True, it is deliberately misleading. However, some possible indicators of life have been found on Mars although these are contested. Two thar I can think of are methane emissions on the planets, and the soil tests by the Viking landers in the seventies, which returned ambiguous results.