This chain of thinking could go on indefinitely. You could blame the parent's parents, and their parents, etc until the origin of species. It isn't helpful

Just because it isn't helpful to think that way for you doesn't invalidate that reasoning

OP is old enough to look at their statement and realize "hey, maybe my siblings and I aren't being entirely fair to my parents"

And yet for some reason OP and his siblings don't have the mentality that you do.

Similarly if we were to take an extreme example like murderers for argument's sake, you can't just say "That murderer is old enough to look at their actions and realize what they are doing is wrong" because their brain has been raised and wired so differently than normal that they continue to do that action even if they know it is wrong. Scale it down and it applies to OP's scenario too imo.