But love is not actually lacking within them.
Based on my own experiences, I beg to differ with you on that one!
For decades, I did try to believe that only the JWs met the requirements of Jesus Christ's "by this, you know that they are my true followers, that they have love amongst themselves". However, after many a hostile snub at a District Convention, I had to reluctantly conclude that the Witnesses displayed love amongst themselves no more and no less than anybody else.
To a degree, this seemed to mirror the local community. My first congregation was a small one, in a thinly populated part of the world. People in general were open, friendly and helpful towards one another. It should have been no surprise that the congregation, too, was much the same. Nonetheless, it did deceive me into swallowing the WTS's propaganda that all JW congregations were like this. It took a long time to wake up to that myth!