Were they on drugs?! How could anybody in their right mind do such a thing?
I haven't read the article, but without saying this is the case, before this became such a strangely contested in the media act of violence, some did suggest it was similar to a very violent attack by Boko Haram against women.
It was said at the time that those in charge had given drugs to those who took part, but what was also cited was the influence of online violent porn from the US. ie they had been shown videos. (This came up in a programme the focus of which was the spread of what had been a "local industry" in the US had gone world wide.) And again, before it became this media fetish of we must all comment on this, that the early reports from Israel indicated the use of drugs.
But, I am not saying this is true, because part of thinking that is as you said, "were they on drugs" because otherwise it is hard to fathom. Although rape as a weapon of war is well known but still not talked about, and is for instances happening now in other countries but western media is bothering to report, let alone endlessly comment. ie there is no sympathy for women across the globe only those who fit an agenda in the west.
Also, which the media again doesn't now comment on but was in early articles, that apart from those who took part in the Hamas attack, were those who are part of criminal gangs operating (or were operating) smuggling between Israel and Gaza, who once the fences were down entered Israel.