There is a sad truth in every community. This existence of truth is that there will always be a bunch of "privileged" beings who already has this hard stumped mindset that new players and beginners are a bunch of whiners.
I have players who tell me verbally that they should always be at the top of the arena to get all the blood tokens and gem because they are the pioneers, because they spend time, effort and money (or not) to be there before the launch.
Seriously? Are we not giving the newbies too much to focus and divert what little resources they have? Are we so inhumanely unaccomodating to the point that we have people who says "I don't see a reason why new players are whining" because of one simplest fact is they can't and are unable to put themselves in the new players' perspective.
This, I present to you, is the finest and ugliest side of human.
Now we have this. But you did mentioned a good point " Are we not giving the newbies too much to focus and divert what little resources they have? ". A newbie should focus on making his squad powerful enough to participate in the event. If a newbie with a limited amount of resources tries to divide his effort on becoming stronger, will still be left wanting on the next event.
I think people don't want to heed the advice that the event is not for everyone. The event is somewhat an extra for those who have already maxed out on what they can get on doing the Story missions. You'll notice that even if you finished 100% of the event, you wont gain much. Looking at Kahuna, he's quite a mediocre unit. You'll barely be able to progress with that unit. You'll be better off trying to promote and train your units and acquire more gems via doing the trials in Story than doing the event.