Mars is already screwed up. It would be hard to screw it up even more.

With our current understanding and technical abilities - no need to worry, they’d all die shortly or bankrupt the host country.

Miracle Max: Look, I'm retired. And besides, why would you want someone the King's stinking son fired? I might kill whoever you wanted me to miracle.

Inigo: He's already dead.

Miracle Max: He is, huh? I'll take a look. Bring him in.

We screw up everything. The question is, can we leave places alone and screw up others instead? Screwing up the moon is probably better than screwing up Yosemite, or the Great Barrier Reef.

Screwing it up today prevents us from doing something useful tomorrow with a more complete understanding.

Patience is a virtue, as they say. I fear the current raft of would-be planet colonizers are not very patient...

There isn't much to screw up on a dead planet.

I'll bite. You know it's dead how? Mind you I grew up reading Heinlein juveniles like Red Planet.

You're right, there may well be some sub surface microbial life on Mars, and we should figure that out before doing anything too drastic.