Does ARAM change people?

I am finding it does, as the more matches I play, the more I realize that so many people are bad at the mode. It truly is strange. Seeing people that are Gold and even Platinum ranks just really sucking at the champs they get, and I'm not talking champions that, according to Riot have higher learning difficulties, like Yasou or LB,which have 10 and 9 respectively. I'm talking champions like MF, Morgana or Malphite, all of which have a 1 or 2 in the difficulty range.

I don't have a "main" champion, and I have used every champ at least once. So even when I get an "unfamiliar" champion, I still manage to go positive, equal or otherwise contribute many assists to more skilled players, yet so many game I get people who get arguably the easiest champions to use and they go 2/12/6 or something like that.. and when I look at their rank, it's Gold or Platinum. If you can't handle the higher skilled champions, I totally get it.. but these champions are some of the easiest to use..

Not trying to call people out.. but I would have thought people at those ranks would have more skill at playing other champions besides who they "main." They seem to do well in ranked or normal's, just not so much in ARAM. I guess it must be the mode? idk..