> is that really reason to go to war though?

Funding armed groups to essentially make war on your behalf does seem like a valid reason for the person being targeted to go to war.

As a general rule, if you shoot someone they will shoot back if capable.

What other option is there?

I don't approve of war (and Trump didn't handle it well). However I also don't approve of what Iran has been doing.

There are two crazy nations I know that can nuke without morals. Hint: Not Iran

Nukes is irrelevant. If someone dies it doesn't matter at all if it was a nuke or a conventional weapon. Nukes can do a lot more damage in one go, but if you are killed by something else you are just as dead. Iran was clearly working on killing people by non-nuclear means as well.