The only reason this seems possible is because you are not fully aware of every part of your mind, and some hidden parts of you are working against you.
You believe that your current awareness is a full awareness, that you are fully aware of your entire self. Wherever you sense the edges of your awareness to be, that is the boundary that you believe is the edge of your entire being. And that there is nothing else beyond it.
But your mind, unless you are spiritually awakened, has parts to it which you are unaware of. There are parts which are hidden behind walls of denial and fear. These parts are essentially unconscious to you, i.e. you are not aware of them in your conscious awareness and this makes it seem as though they do not exist. There is more to your mind than you realize.
If you were to ask most people if they have an unconscious mind, it would be a complete guess, because really you can't be aware of the unconscious until it is made conscious. So you have to take someone's word for it that you may even have unconscious parts to you. But unless you are aware of the presence of God, there must be some parts of your mind which are outside of your awareness.
Now, simply because some parts of your choosing mind may be outside of the scope of your conscious awareness, it is possible that those parts of your mind are active and are choosing to make things happen, but without your knowing it. These parts of your mind are filled with beliefs and thoughts and attitudes which do express and do create situations and events to reflect what it believes.
Particularly, the unconscious mind is usually a repository of darkness, self-attack, guilt, hatred, and all manner of insanity. And this tends to be so denied that it shows up in your experience as though it is outside of your body, and embedded into or laid on top of other people. You experience it out there as though it has nothing to do with you at all, and yet it is your own hidden self-hate.
So then, it seems to your conscious self as though stuff starts to happen to you that you did not consciously want or remember choosing. And to explain the origin of these things that happen to you, being unaware that you chose them yourself, it seems to make sense to now find some "other" source of these things. Like other people.
So the mere fact that you have a split mind which is partly conscious and partly unconscious, automatically puts you into a situation where you see yourself as being victimized. Choices are being made, a will is performing its desires, and someone somewhere is deciding things, but it doesn't seem to be yourself. So automatically, you will look outside of yourself for the cause.
This is the origin of all scapegoating, all blame, all perception of being a victim in any way, all anger towards others, all attempts to find other people guilty or wrong, and all belief that it MUST be someone else's fault, simply because you are not aware of what hidden parts of yourself are doing to yourself. You become hell-bent on finding someone else to be the cause of your condition, not realizing that YOU are the cause.
Given that you are not aware of the full scope of your whole mind, and given that the hidden parts of your mind are still believing that you are guilty, and given that those beliefs will lead to self-punishment, it is no wonder that once those punishments start to happen, you're going to be desperate to find out WHO did it to you. You'll think it's not you.
It can seem to be difficult to accept that you chose suffering or difficult situations or major problems or sicknesses or pain or fear. It can seem like there is just no way that you would've wanted this situation, and that there is no way that you - your conscious self, would choose this. But you're not aware of your whole self, so you don't really know that you chose it, or why.
Over time, with forgiveness, which is really just the insight that you've been doing EVERYTHING to yourself and NOTHING has happened to you that you did not choose - unconsciously or otherwise, you will become more aware of the content and attitudes hidden in your unconscious. The unconscious will be integrated back into awareness, you will uncover your secret sins and hidden self-hates, and through healing you will come to a fuller awareness of the whole of yourself.
It is in the light of that fullness of who you are, rather than being a little portion of yourself, that you can recognize that you cannot possibly have been victimized. You will be honest in admitting the truth, that you have been doing this to yourself, you did plan it all along, and there is nobody else to be held accountable.
If you can see and accept that you really DID do this all on your own, to yourself, without needing anyone else to explain why things happened, then automatically everyone else is innocent and you have hope of freedom. But this DOES require that you be AWARE, i.e. able to see, that you really ARE doing this to yourself. Then you will not even think to blame it on anyone else because you obviously are the cause.
Because now that you are in your full mind, you can choose again, and decide to stop hurting yourself. You can choose life. You can give up your death wish. You can let go of your self abusive attitude. You can stop hating yourself and stop condemning yourself. You can stop believing that you are sinful or guilty. And you can come to realize that God still loves you because you have not really done anything at all.
Awareness sets you free of the delusions and illusions of suffering, that you conclude are caused by anyone other than yourself. The belief in your fate being chosen entirely by "other than me" is a choice for death. And even then you are still doing it to yourself. You do not have to die.
Increasing your awareness through undoing of the blocks that keep the mind in the dark, will set you free and bring you back to life. This is the time of your resurrection. This is your return to who you really are, free of the illusion that you can suffer at the hands of another. It was never anyone else's fault.
The secret to salvation is that you are doing this to yourself, and have been all along. And yet you have done nothing real at all. In this view, both you and others are equally innocent, and all is forgiven and released.