In their mind why would they ?
Unless your a JW your going to be destroyed by Jehovah/Jesus at Armageddon because your a part of Satan the God of this system of things world .
If a JW helps a non witness who has shown no interest in becoming a JW then they would be considered helping and supporting Satan`s system of things of this world that is lying in the power of the wicked one .
In contrast to this though is this .
How many aged and infirm Jehovah`s Witnesses do you know personally that are no longer cared for by family ,and certainly not by the Organization of Jehovah`s Witnesses and are in Church funded , or Government funded institutions and cared for by these institutions that they considered a part of Satan`s system of things or Babylon The Great ?
I know a few.