"Organic material and methane finds can’t be tied to biological processes"
That is the key comment there. Organic compounds just means carbon containing compounds and does not necessarily imply the need for living organisms. For example, amino acids (the building blocks of proteins) such as glycine, alanine and glutamic acid have been found in meteorites but they derived from standard chemical reactions and not from anything living.
Similarly, the methane could arise from seasonal sublimation of ice that just happens to contain methane from Mars' ancient atmosphere when the volcanoes where far more active.