I feel like sending earth worms to Mars is like sending pigs to South America. Perhaps there is nothing living there... I don't know. But do we need to have such an imperialist attitude with planets too?
It's a barren rock. You're not displacing native lifeforms, because there are no lifeforms. It's as imperialist as shouting "I'm the king of the world" in Antarctica.
Some things live in a realm "beyond good and evil" and are just pure creation. I think Mars terraforming is one of those things. We are creating an entirely new system within which new goods and new evils might subsist. The entire notion of "Imperialism is bad" is a banal historical platitude in this context.
I wouldn't judge it that bad. "it" is not a popular opinion, and the downvotes are due to a sensitive topic and a biased crowd if you consider the time of your posting. "it" seems popular because, ironically, everyone else just does not care enough to spread their seeds of wisdom.