There were major wars and conflicts happening well before 1914 and of course continuing after - if you read through history without the JW inspired 1914 mention detector engaged then it really doesn't stand out.
The 1914 date was something they plucked out of the air in the mid 1920's. Prior to that they were still talking about 1874 as "the date of Christ's return" and they had a list of "evidence" including (I kid you not):
- Barbed wire
- Telegraph machines
- Other random inventions