At least one Mars lander has discovered ice and evidence of briny water beneath the soil. The fact that we have not sent a microscope just baffles me.

I do get the sense that for whatever reason there is a bias against explicitly looking for life. I don't think there's a big conspiracy explanation. I personally think it's what I call the "boring universe brigade," the skeptic ideology that came to dominate science starting in the 1970s that treats fascination as a contrarian indicator. "If it really fascinates people it's probably bullshit."

If there's anything beyond that bias it's probably a fear of triggering fundamentalists.

Edit:

Here's one bit of evidence for possible near surface water at a landing site:

https://www.space.com/209-life-mars-scientist-claims.html