My 2 cents as a Dutchman:
Whenever newspapers use 'jehovas' JW do perceive it as hostile and disrespectful.
I'm not quite sure the media intend it that way too.
"Jehovah's Getuigen" is simply way too long for the limited space in newspaper (headings). Many people also really don't care about it. Do people and media in the US pr UK normally say 'Mormons' or 'Church of the Latter Day Saints of Jesus Christ'?
It's not really intentionally hostile or offensive; it's just that people don't care enough about all those wacky religions that have strict preferences about how they want to be named.
Side note: The official spelling rules say proper spelling in Dutch is "Jehova", not the English "Jehovah". Many media use official spelling, much to the chagrin of the 'Jehovas'