Actually, you'll find that pretty much all the scientists arguing there WASN'T evidence of life in the rock were evolutionists as well.
And the assertion that this is evidence of bias against creationidiots is extra-stupid for a variety of other reasons. First, I didn't know part of creationidiocy was a blanket assertion there's no life outside of Earth, and I don't remember a single person presenting the case that there was life in the Mars Rock dancing around saying it was evidence of evolution.
And secondly, it's blatantly obvious that the media is more interested in a story about life being on Mars than a story about life not being on Mars; has nothing to do with creation or evolution. It's just based on which side is more interesting. NOBODY is excited to read an article about how there's no evidence of life in the moon rock. Also, the people presenting the case there was life went first. That in and of itself got them more coverage.