My problem with the game is that movelists are short and even then often have moves that feel useless. Some strings are unsafe on block for no reason, or have the same purpose as other strings making you think "Why does this even exist? What is it for?"
Example: Some specials have an insane amount of start-up AND recovery frames. I started playing the game a little more when Nightwolf came out and decided to try to learn Thin Ice Sub-Zero. One of his specials, Death Cicle-Barrage, has 30-something frames of start up and is unsafe on-block. It doesn't do a lot of damage on hit, and while it is a pretty good chip damage move on-block, remember that is unsafe. This creates a move that is very situational, which is fine on paper, but in a game that is neutral heavy and has limited movelists/variation options, getting moves like this does NOT feel good. I feel like Kung Lao is in similar situation. A lot of his strings are unsafe on block, have highs that can be ducked and punished, and/or has gaps in them. His variations suck, his teleport has a billion frames of start-up, etc, etc.
Yes, you can get results with Kung Lao and Sub-Zero. They are actually pretty good characters. That's not my point. My point is that they just don't feel good to use because NRS has decided to make them feel very limited by giving them situational moves and shitty variations. When I watch a Kung Lao player in tournament, like maybe Foxy Grampa, I noticed a lot of Kung Lao's gameplan comes down to using Amplfied Z-Hat into a throw set-up and to try to fish for the the throw KB. That, and using the same 2 maybe 3 strings over and over again because you don't really have many good options to use in terms of strings. And if you get a hit? Usually the same bnb midscreen combo, or bnb corner combo depending on where you are at on the screen.
There is not a lot of variety in this game, and a lot of options just straight-up suck. You could have a really limited character, meanwhile there are characters like Sonya, Geras, Erron Black, etc. Even characters like Liu Kang seem to be giving people a lot of trouble because of frames or some shit. That is the #1 reason why I don't play a lot and I can see how this would make people get more rage induced that other FGs. Your options are: play a limited character with a gimicky gameplan, or play a braindead character that is easier to get results with. If you are a Johnny player (just using this character as one of many examples) trying to get results, and you are constantly having to deal with characters like Geras, I can see how the game will feel almost unfair and thus rage inducing.
To be fair, this is my fairly inexperienced hot take.
TL;DR, you have characters like Johnny, Kung Lao, etc, that often feel limited (especially in pre-patch) but then you have characters like Geras and whatnot. The deference in design can be infuriating. How come one character can get useful strings, good damage, easy Krushing Blows, and a really good Fatal Blow start-up -- but another character gets a gimmicky gameplan and a movelist full of situational filler? While you can get results with the latter, they just do not feel good to use and even in times almost unfair.