This is not to be blamed on WhatsApp whatsoever, but on the carelessness of the victims or intending victims. And this has nothing to do with the end-to-end encryption, they are different things.
WhatsApp is not an antivirus, so it's not responsible for the security of your gadget. That's why you should be aware of the havoc that what you download or the link you click on can cause. This is not the first time people have been downloading malicious programs through online communication, so WhatsApp shouldn't be blamed for any reason. We are responsible for the safekeeping and protection of our gadgets.
They must know their responsibility on how they can make their selves safe from any potential threats that can possibly cause them harm.
There are lots of attempts would provably come up and we must be aware about simple logic that if anything is to good to be true its not true for sure that they won't get scammed easily by those criminals intent to harm people and take advantage with their innocence.
WhatsApp is not responsible for any harm they might encounter and they must know what has been implemented on that platform so that they also would know what to do and how to became a intelligent user of that app.