I mean that in every sense it can be asked. I've noticed sometimes people can become sympathetic to a criminal if they've had a bad past and also noticed some of the criminals I've associated with feel they can justify their actions as those they grew up learning.

I find I personally sit on the fence with this with most crimes - a guy's got to do what he can to survive, right? But I don't think anything can be used to defend murder, rape or similar bigger crimes.

It is something I've toyed with in my head though. I've never had it as tough as some people have so I could never truly empathise with them. So I ask you all,
to what degree can a person's upbringing be used to excuse their actions?

In a legal sense, in a general sense, in any other ways you might think of. Perhaps you might even think a general rule applies with exceptions? Think about it.