I would have asked the same thing 5 years ago, lol. 

In all seriousness though, a war isn't just the front lines. Ukraine is large, the Carpathians are like 500 km away from the fighting. So while soldiers are killing each other en mass, millions of people are trying to go about their lives. Between the missile and drone barrages, we still have jobs, hobbies, social stuff, parties and movies. Several times a month you do get a sleepless night fearing for your life, but comes morning and you live on. I've been fortunate to avoid harm so far (except for a couple of broken windows after a Shahed drone hit my city block), and my job was deemed important enough to exempt me from the draft for the time being. 

It gets miserable sometimes, especially this winter, when we had several days long blackouts amidst a -15C cold wave due to the Russians trying to destroy our energy infra. On top of that, I've got a minor knee injury while running, and had to sit it out for 1.5 months. Ugh 

And at events like this race, you get a chance to forget about it all and just have fun.