Of course it's one's own responsibility buying altcoins without any knowledge or experience. Hopefully they learn from it when they've bought the wrong altcoins and hopefully it's not an expensive lesson.
The reason why most newbies are choosing BTC over BCH is because they see the current value of the two and from that they make their decision and also because BTC is very popular thats what drives most of the people into investing into that coin.
Traders prefer Bitcoin Core to Bitcoin Cash because of the rank on marketcaps and their value. Newbies choose Bitcoin Core because they are introduced by old traders