@roman_k They're wrong, not you. Know your limits. These things happen, and it is really sad.
A lot of young people go to shelters to adopt a dog, and this is not an inherently bad thing. In many ways it's a good thing, but I think the culture around it really glosses over or really ignores the challenges of bringing a dog into your life, especially ones that you didn't get to oversee through formative periods of their socialization and growth. When you luck out and get one that can be clipped on a leash and walked around a city with no problems, or who can play well in a dog park, or who doesn't need to burn off a bunch of energy off leash—well, you lucked out, in a sense. But a lot of folks think that's what they're getting when they bring home the dog, and are woefully unprepared for the rainbow of alternatives that can arise with owning any animal, really, but especially ones that might come from early developmental trauma. Like people, they need healing and resources.
Dog training can take a lot of time and effort, but working with reactive dogs can be near a full time job, and a lot of shelters/agencies don't provide adoptees with any resources to deal with reactivity. I feel like there should be a mandatory 4 hour video series every dog owner needs to watch, whether they adopt or purchase from a breeder, but particularly if there are signs of maladaptive behavior in the dog they wish to adopt.
I've seen countless young people go from coming home excited with a new family member to being stressed out realizing only after the fact what they committed to.