Since your vegans aren't able to fight against predators, they will have to develop better hiding and sneaking techniques and strive around as nomads. Why? Once you set up a permanent residence, you will leave more traces, which means it will be more likely for predators to find you. (Bears learnt that there's honey in bee hives... Not compare that to humans in houses! Bonus point: the humans don't hurt, contrary to the bees)
This means at the same time that they won't be able to develop farms, so they will have to get by on what they find on their way. This might work out in some tropical forests, but it would forever prevent them from going into territories with snowy winters since they would probably not be able to survive. (Your question makes it seem that they would try to shoo a pack of hungry wolves with some frozen herbs...)
So requirements for your vegan humans would be:
- Easy to find easily digestable food
- Terrain that allows to easily hide
- Not enough predators to rot them out completely
In conclusion: They would not be different from herbivore apes, living in tropical forests. They might be able to use very basic tools (a stone to crack a nut?), but anything more advanced would at least require the need to forcefully defend yourself from predators (which, in turn, could/would hurt animals).
Your question asks about how this would affect military industry; I'd say there won't be any industry at all.
Military industry would require groups of humans fighting each other (or at least pose the threat of doing so). Why would your vegan humans try to hurt other humans if they aren't able to hurt a predator hunting them? There wouldn't even be a tangible benefit (other than drawing predators to you with the smell of blood, which might erase your whole group).
For other industry, most of them would require developments on top of fire (steam engines, melting metal, cooking/baking stuff) which would put your humans at risk of being found and destroying their habitat (also, it would kill insects flying into the fire!).
It seems unlikely your humans will ever invent something more advanced than stone knives (Or find a reason to do so).