I think this fails the base rate fallacy test; there are lots of times when mucking with an ecosystem hasn't caused problems, but nobody talks about those.
Failure of an ecosystem is very severe. What does the base rate fallacy test have to say about playing russian roulette? No one talks about the 5/6 times it doesn't cause any problems.
It's not clear it's not a problem, either. As you cite, we don't know either way yet.
"Let's be careful mucking with an ecosystem" isn't negative, and there's a lot of historical evidence such caution is necessary.