Would you approach a pack of wolves? Of course not and you wouldn’t want to approach an alien or a group of aliens. Lord knows where they have been.
Think about it. Theses are aliens. They came from outer space. If you didn’t know they existed before their visit then you don’t know what else exists out there. We’re talking disease on a universal scale people.
You touch an alien you could end up with a cosmic communicable disease. The rotting insides become a precursor for your decaying outsides.
Better not to touch them before the Hasmat team sprays them down.