SO how about whe you’re beating the opponent blow for blow then out of nowhere they hit you with two crushing blows and win? You think that’s fair? It’s ridiculous and it always happens and it’s unpredictable that’s frustrating asf. Especially they fight like a coward. Only people that enjoy this game are cowards.
The only thing that's unfair about the KB's is that some characters have a ton of them with easy activation.
Outside of that, there is literally nothing random about KB's. They all have conditions that need to be met in order for them to activate AND on top of that, the conditions are listed in each character's move list! The conditions are literally spoon fed to us. If you're expecting to play any game seriously and competitively, then you're being lazy and not doing the research to learn each character's KB's and the conditions to activate them.
If you're NOT serious about playing competitively (I'm not), then just accept that you're going to lose to players who have not been lazy and who have put in the work and doing the research necessary.
Outside of that, I still certainly agree that IF you claim is that some characters have more KB's than others and that they're easy conditions to meet, then that's a valid claim. Being unfair in terms of them being unpredictable is not a valid claim when the info is in front of your nose.