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Why do many scientists doubt that the Allan Hills meteorite contains fossils of Martian life?

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Planet TOI 700e — extraterrestrial life An illustration of the Earth-size planet TOI 700e orbiting within the habitable zone of its star. The habitable zone is the area around a star where liquid water, and thus possibly life, can survive on a planet's surface. Its Earth-size sibling, TOI 700d, can be seen in the distance.

The claim that the ALH84001 meteorite contains fossilized Martian life remains highly controversial and lacks broad scientific consensus. While researchers in 1996 identified organic compounds, iron mineral crystals, and microscopic structures resembling fossils, subsequent investigations have provided alternative explanations for these findings.12

Scientists generally doubt the biological origin of these features for the following reasons:

Nonbiological Processes: Many of the observed characteristics, including the carbonate grains and mineral crystals, can be adequately explained by inorganic, geological processes rather than biological activity.1
Inconsistency with Known Life: The features identified in the rock are not entirely consistent with the characteristics of known microfossils or living microorganisms found on Earth.1

Because these lines of evidence are ambiguous and can be attributed to nonbiological origins, the hypothesis that the meteorite provides definitive proof of extraterrestrial life has not been widely accepted by the scientific community. Nevertheless, the study of such meteorites continues to inform our understanding of whether Mars may have once been a hospitable environment for life.12