Yes, I think that it is NOT intentional cruelty. However, if one steps back and looks at a situation and is honest with themselves, yelling at ANYONE over an extended period of time is clearly cruel. I think adults often forget how fragile teenagers are, because they so often seem like know it all smart @$$es. They are starting to look like adults. They are smart and can engage in conversations, and they have interesting ideas. But their brains are still really undeveloped and will remain so until about their mid twenties. They are till developing a sense of self. They are still very elastic and able to be molded, and hurt.

The OP is in a really tough situation. When people have given up on trusting you, it is extremely difficult to prove you can be trusted. And I think there is a good chance any confrontation about the yelling is not going to go well.

I think during a calm time, the OP needs to go to their parents and ask to talk. They need to make it clear the understand why no one trusts them. They need to make it clear that they want to change. Probably they need to see a therapist and explore family approaches to behavior modification as well. I think they need to then explain to their parents that yelling and accusations don't actually help, that being punished for telling the truth doesn't help change. They can explain they understand WHY the yelling is tempting, and don't blame their parents, but even if it is understandable, it doesn't actually help.

I guess one of my main concerns is that this family has already practiced this maladaptive dynamic for SO long, that unless they have family counseling and behavior modification interventions for EVERYONE, things won't get better. Yes being a chronic liar is clearly very problematic, but something in the environment has encouraged and reinforced that behavior. And ALL of that needs to be addressed as well.