Because their foundational teaching is that 1) you are not justified 2) Jehovah is not your father 3) Jesus is not your Mediator.
Not exactly the good news gospel hour is it?
YOU ARE NOT JUSTIFIED
The ...“other sheep”, [non 144,000] are in a different condition. …They are still human
creatures, not even justified, - Wt. 38 p.104, 105
What, then, about true Christians...? These have not received “the free gift of righteousness” Wt. 6/15/11 pg. 15 pars. 19-20
JEHOVAH IS NOT YOUR FATHER
“he is not yet giving the ‘other sheep’ the standing of sons….
they address him prospectively as ‘Our Father’.” - Wt. 8/15/45 p. 253
JESUS IS NOT YOUR MEDIATOR
in a “strict Biblical sense Jesus is the ‘mediator’ only for anointed
Christians.” [The 144,000] - Wt.4/1/79 p. 31
“Christ does not act as Mediator of the new covenant toward them, [the ‘Great Crowd’ or average JW member] yet they benefit from this covenant through the work of God’s Kingdom.” - Wt. 2/15/91 pgs. 15-20 par.11