To me it's just another indication that some players just don't like a challenge/difficult content, wich is totally fine. It's just a matter of preference. Generally speaking most content is very doable with a mediocre roster, so it's not like ea/cg only caters to the players that do like challenging content.
Recently the devs have started adding some more challenging content to also please the players that do like challenging content, wich is awesome. It's mostly just 1 tier that is entirely optional and not that rewarding, wich is also great.
Some players just can't handle that and start the complain train. Unfortunately they always blame it on the event and it's never due to the choices they made themselves. It's either only for whales/p2p, or it's just RNG. Atleast with this event they can only blame RNG.
Personally i feel like blaming it on RNG is just an excuse to not be confronted with their own shortcommings. Sure, RNG plays a role in the outcome of the battle, but i'm reasonably sure that if i played the event 10 times, i would beat it 7/8/9 times, meaning you don't need good/godly RNG to win, but horrible RNG can cause you to lose.
However, if you have no clue what you're doing you actually do need godly RNG to win, but does that make the event too RNG dependable or is not knowing what you're doing to blame? needless to say i think it's the latter. I'm not just saying that to boost my own ego, i've seen threads where people were calling an event unbeatable, untill they listened to the advice given in that same thread and cleared the event.
tl;dr
Moral of the story is that it's fine if you don't like an event, but also realize that you yourself and your own preference in content are the reason you don't like the event, not because there's something wrong with the event itself. No need to come up with excuses and be offended when someone says "git gud".