The fact that you live a seemingly righteous life but be subjected to burn for eternity because you don't truly believe in someone is just
When comparing the average human lifespan to eternity, 75 years is but a nanosecond in the ripple of time. And remember, most humans lived to about 28-30 a few thousand years ago. But the fact that what you do in that finite nanosecond is how God determines where you spend the rest of eternity, seems a bit cruel. It's like Breh... can I get one more try.......or two? Third times a charm?
I don't perceive God to be that restrictive. And in the Abrahamic faith sense, for a God to be everywhere and in everything, there is no place we can go to escape the presence of God. If this be true then we can find God among other people, and in other faiths, in other cultures and languages, etc.
The New Testaments states that there is only one way... one road. But what I have found, people who state that something is the only way or only option, are being manipulative and after power, because, of course, they are the only ones who can show you the way. You can see this on a smaller scale with cults. You can see this on a grander scale with Muhammad. If God is transcendent, let him be transcendent, and not let the human mind, that is by nature psychotic and divisive, constrain him into a box.
To answer your question, the bible states that Christ died for the whole world and that what he accomplished is complete. For us to have to "accept" Jesus (say this magic formula and you'll be saved and believe in your heart), it turns salvation (a gift that had been given free to all and is complete) into a work (you have to do A, to get B), and negates his grace.
all the fun people sin. 
