Yes, that does make them a bad person, and that makes it impossible for them to be more than just an acquaintance to me. And it also makes their religion--or at least their personal interpretation of it-- a bad religion. My imaginary friends don't get jealous of my real friends, and if yours ever do, you might want to consider pretending to break with them instead of turning on your real friends. It's up to you to determine if your imaginary friends have ever actually prevented you from making a real friend.
Ethical development has come a long way over the last 5000 years, but even the semitic monotheist religions have all had "That which is hateful to you, do not do to others," for the last 2000. And yet the faithful still put their own hateful words in the mouths of their gods or their prophets for the credulous to hear and repeat. They do it for money and for status, and care little for the consequences.
It is wrong. We can explain its wrongness with ethical treatise, and demonstrate the wrongness with game theory and Monte Carlo methods. Private behaviors of any sort are fundamentally unsuitable as discriminators in public life. To the extent that they leak, only that portion that is visible to the public should ever matter.