The problem is when you work in a place where the management are jws and you are not.
Actually, at least in the United States, the way out of
this one is rather simple: call your state Dept of Labor and/or
Unemployment agency. Tell them your employer is harassing you and has
created a hostile work place. They will contact employer and tell them
to knock it off. That letter will probably include a note that the only
reasonable company policy is to enforce a "no politics or religion
policy." If they fire you, you can make a good case that it was
retaliatory.
I was on the sidelines but had a good view of two
such fights (no JW's but similar issues). One employer lost about
$100K, the other $250K.
At my last employer (a 28 day rehab
facility) I had a co worker who was a JW that didn't know I was an ex,
as I respected the company no religion or politics policy. When I heard
him preaching to patients I reported him up the chain of command. He
left shortly after, I think HR made it clear he could shut up or leave.