hiding and congregating animals or people

Hello all, 

I've two autistic kids, both diagnosed, and both into games. Now I'm not overly concerned as I love technology and games myself and they are always helping me with things tech orientated. 

However, I do have a concern about how they act on games like Pok Pot and Minecraft, they will happily hid characters inside other things, congrats them together and if the games allows, blow it up. They do the same with animals, spawning loads on Minecraft then build them a trench, cover it up and then throw in several bombs to explode them all up, all while laughing. 

Am I thinking to much into this or is it just a social trait issue that they have, what with being on the spectrum. I'm just concerned. I've spoken to them both and they don't released they are doing it sometimes, and other times they say it's just funny... 

Honest responses please, I'm thick skinned. haha. 

Thanks all.