Do you have to know God to show true love?

In 1John 4:7, it says that if you love people you know God. What does this mean for Hindus, Buddhists, Atheists, etc. who love people? Can only Christians truly love people?

In one sense, it seems like this question doesn't really apply because this letter appears to be meant for a group of Christians.

But, let’s say it did…..
There are many ways that any person can know God.

You can know God through His creation. Psalm 19:1 The heavens declare the glory of God; the skies proclaim the work of his hands. Day after day they pour forth speech; night after night they display knowledge. There is no speech or language where their voice is not heard.

You can know God through morality. Romans 2:14 Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law, since they show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts now accusing, now even defending them.

Here’s the problem. Romans 1:21 For although they knew God, they neither glorified him as God nor gave thanks to Him, but their thinking became futile and their foolish hearts were darkened.

You don’t have to be a Christian to love people. But, you do need the sacrifice of Christ on your behalf to gain the forgiveness of sins. Therefore, the more important question is; how can Christ’s sacrifice apply to me?