Nobody likes getting nerfed, but Warframe players have the image of being particularly allergic to it. After every nerf you have people proclaiming that this was the final straw, that they are done with Warframe, and that the game is going to die. In other games, people are diappointed, sure, but they don't consider quitting the game. Even if they spent money on things getting nerfed.
So what is the difference, are Warframe players simply entitled and immature? Well, that would be an entitled, immature, and obviously silly opinion to hold. The people playing Warframe are the same people that play other games. Given that, the cause can only lie with Warframe itself.
What then does Warframe do differently to other games, in regards to nerfs or otherwise? I'd like you to consider 2 possible reasons:
In other games, you might have noticed relatively frequent, small changes. 5% less this, 5% less that, and maybe a small buff somewhere else to compensate. This gives players the feeling that the developers know what they are doing, the balance was not quite right, but close, and the things getting nerfed may be dropped in favour of something else, but they remain functional. In Warframe however, nerfs are big. 50% less this, 70% less that, signature ability removed. The player reaction is predictable: "So you have no idea what the hell you are doing, and I'm never going to touch that thing again."
Making (a lot of) players not use the affected items anymore is the sole point of any nerf in Warframe. But Warframe is all grind, there's nothing else to the game. People wasted days, weeks, sometimes months, to obtain and optimize the item DE just (on purpose) made them not use anymore. Maybe you've heard the phrase "DE isn't respecting the players time". Well, it's true, isn't it?
In summary, things take a lot of effort and time to obtain, they get nerfed by popularity, the severity of nerfs is not aimed at balance, but at making players stop using the item, and balance in general seems like guesswork at best. Obviously this is dissatisfactory for the players affected.