In my experience, most people don't even try. I know many atheists that lead holier lives than the vast number of nominal believers. A person is defined by their actions, not what they profess.
I hardly expect people to be perfect but most people put approximately zero effort into following the tenets of their religion. They follow their religion when it is convenient or little effort is required, but routinely and habitually engage in behaviors that they are supposed to abhor.
Those are some pretty wide generalizations, but I can see some of your underlying reasoning. Still, I know many people who agonize over what is right and what is wrong--as defined by their religions. It's difficult to live up to God's standards, but to say that "most people don't try" or that most put "zero effort" is not accurate, and it's not for you to judge.
You don't but God does...
Leviticus 19:2 "Speak to the entire assembly of Israel and say to them: 'Be holy because I, the LORD your God, am holy.
Matthew 5:48 Be perfect, therefore, as your heavenly Father is perfect.
Matthew 19:21 Jesus answered, "If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me."
That's the problem with the holy athiests. They may be relatively good, but that isn't going to save them in front of a perfect holy God. They still have sin in their life and there is nothing good that they can do that they shouldn't be doing anyway, to make up for it. And rejecting God and God's plan of salvation is a pretty major sin in itself. But ultimately that's the one that condemns them.
If they accept salvation their evil deeds are wiped clean and they are made perfect through the forgiveness of sins. If they reject salvation, then they are judged by their works. But scripture already tells us "none are righteous for all have fallen short of the glory of God" (The glory of God in this case is holy perfection)
To be judged by your works is death, unless they meet God's expectation which is perfect.