Not necessarily.
For instance, my friend was abused as a child (sexually, as well as physically and emotionally). She now goes to therapy and counselling. She is struggling, is bad at developing relationships, is quite introverted but at the same time is desperate to please (maybe a kind of defence mechanism as a child? Pleasing your parents might make them love her?). She has suffered a lot, and is still a really good friend, but she has more control over her life now. She has no family to support her, so I've been to a number of counselling/therapy sessions with her (most are 1:1, but especially in therapy they seem to want her to bring someone to rely on/feel familiar with). I can't believe she's gone through it, it makes me feel so angry- my friend also deals with anger problems (mostly self-harm, she doesn't hit out she hits herself).
A child has no chance of therapy or counselling. Often they are living through the abuse, not the issues of after abuse. An adult murderer will be dealing with the past- an abusive past, which is hard, challenging, emotional and difficult, and leads to so many feelings and problems- but a child will be right in the thick of it, you could say. They have no way out. They'll be coming home to be hit or sexually abused or any number of things, and they can't escape.
I think the difference of age means a difference in dealing. There's also a large difference in people. Like I explained above, my friend had a problem with self-harm (although she doesn't do this now, I think, she still has a tendency to self blame and to hate herself- she has terrible self-confidence, and doesn't think anyone can really like/love her) by turning the pain and anger she suffers, and in turn needs to release, onto herself- a way of almost 'punishing' herself for what's happened- she can blame her parents obviously, and is starting to manage that, but blaming your parents is actually a very hard thing to do, to be able to say to someone 'I hate my parents. They made me suffer. They're not right. They're wrong. I was just a defenceless child, and they abused me.' She wants to blame someone, and the easiest victim, especially after years of being told how terrible, ugly, wrong, needy etc; she is by her parents, is herself.
Other people might turn outwards, and direct their pain and anger onto someone else- I think that's why children who watch one of their parents suffer domestic abuse are more likely to abuse their partner (this is more common in boys, and girls are normally more likely to become a victim, so learned behaviour, but it also works the other way round as girls either follow their mother if she is the abuser, or attempt to 'fight back' for their mother by abusing someone- a lot of children who witness domestic abuse obviously do not become abusers, most of them probably won't, but it's one of the possible results)- they can blame someone else, hate someone else, turn all their pain onto someone else.
How can a child realistically speak out? SS obviously, sometimes they can be taken into care, but a child who is being abused and not spotted will have no real way to direct their anger or pain safely. I remember as a child (non-abused) that when I was angry, I'd punch my pillow or my bed or squeeze something really hard. That was normal teenage anger. What would I have done if I had proper, difficult pain and anger stemming from being abused? Where I could get rid of the hurt and other emotions?
Adults can vent more safely- they can speak out, they will be heard, most aren't being abused at that time. Can children really do that? Being in the thick of abuse can never be the same as after the abuse, and the effects are terrible, hard, difficult and emotional (as I said before), but different.
^^ Is all stuff I've gleaned from my friend/my opinions/going to the therapy/counselling with her. Of course, my friend could be different, but the therapist doesn't seem to think so. I might be wrong obviously as I'm lucky to have no direct experience of abuse.