What really makes people so frustrated is current Ranked Arena system of rewards. You can work very hard for a whole month and all your determination and time spend on it goes into vain when you get a silly reward for it. Ranked Arena should have full reset of rank every month for everyone and rewards based on rank you got to, without having to climb to Six Paths.

Begging and toxic comments are very common but nothing work so well as just ignoring them. In every competetive part of every game there always will be people like this. You wish to block people on forum from posting their happiness of getting through that hell finally- sorry from my side for joining that too- but well then we shouldn't get server ranking for Arena and titles for it neither. But that's not really the problem. See, whole game is about geting something and bragging about it- even when you don't do it on your own- see: chat messages when someone draw a rare ninja, drop something nice in event. Titles and rankings. System messages about Ranked Battle and things like this. All of this is a way to heat up competition in certain area. And with things like this- there always will come frustration and toxicity from side of some players. As I said earlier- best way is to build up immunity for them and ignoring.

Since you mention your little cousin in comments- as a mother I will tell you that- if you let a kid/teen join any online competetive game, then you won't save him/her from toxicity, salt and insults for every litlest thing. Instead of pointing out forum posts- teach them to not join these toxic people and learn to not get their words into them so much.

And, like I said before- real problem is rewards system on arena, it wouldnt be so frustrating if anyone could get stuff for their rank every month. And that would be fair too, since it does need rather a lot of work and time to grab any higher rank in there.

Good luck getting to Six Paths and little to none trolls and toxins on your way there!

Well, that's the other thing that builds up frustration too- as for me as soon as I reach the rank, I stop joining ranked arena, since I dont care for server ranking. Some people do care that's why they still fight there, to grab some more points. Personally I have met some Sennin rank during my way to top there who told me that he fight there still just to troll others and for fun... But they should be matched up only against other Six Paths- as mentioned many times in suggestions about arena. And situation when some Jonin rank, for example, get to fight with crushing team of Sennin there, is just another hit.