You think ONE person can't be unloving, not gentle, or greedy? Have you ever met or interacted with another human?
Because if you have, then you'd know that they absolutely can be. You must just be making excuses as for why all those people don't count, which I'm sure is a fallacy of some sort.
The article implies when it says "In short, James tells us that true religion is a devotion to God, demonstrated by love and compassion for fellowmen, coupled with unworldliness" that you must be a Christian to have true religion. Or at least follow the Abrahamic God.
To your meaning of true religion, can someone who is follows a non-Christian faith have true religion?