It's very simple. In Matt.7:1-5 Jesus says "judge not" and that individuals will be judged according to what judgement they imposed
on others. He also advised to remove the "rafter" in your own eye before you go removing a splinter from someone else.
Take a good look at what Witnesses preach door to door: the moral condemnation of others, how to be happy, how to
have a good family life and so on. Meanwhile, they swallow anti-depressants, secretly view porn, lead "double lives",
and - in particular - suffer from families breaking apart and the loss of Witness kids, as most "leave the truth".
There is no reason for them to preach to others about massive situations that they cannot solve themselves. Jesus says so.
It's as simple as that - and no amount of attractive pictures printed in the Awake magazine changes the situation.
They are dragging themselves out in field service without solutions to the problems they commonly preach about.