I think I stopped doing that sort of thing when I grew up and stopped being teenager. Now that does not mean that I have not tried to exterminate ant colonies since then, I have but not simply for the fun of it or because I was bored. When I have done such things as an adult it was because the ants were on my turf and becoming an infestation and a nuisance. It which case I used more scientific extermination tools to erradicate them rather than just kicking the hill.

Therefore providing the aliens do not allow their children to "play with guns" then it would only their adults we have to be concerned with. In which case unless we are intruding on their territory, stealing their resources, making a mess of their backyard then they will probably ignore us or at most discretely observe us. Only if we become a nuisance or a threat would they be likely to try and exterminate us. In which case they would probably do so very quickly and efficiently and without us probably even being aware it was aliens doing it to us.

As has already been said it is hard to believe that any species capable of interstellar travel would be that interested in any resouces earth had to offer. There are plenty of other places out in space to obtain those and in much larger quantities.

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Note 1. All requests for planetary demolition must now be submitted in quadruplicate on form UX-565/B4 and be counter-signed by the assistant administrative officer for interstellar traffic calming - department QG-7. Subject to approval by the chief planning officer and the infrastructure development coordination sub-committee.