Objective reason: humans have done the most change to the planet (and have put stuff into space). No other species has done that.
I think we have a long way to go to catch up with algae.
I agree with you, it's not obviously clear what "advanced" means in this context if we don't automatically equate it with humanlike.
As far as we know humans are the only species to leave Earth’s gravity well. No other species has been able to do that in 4 billion years.