Realistically it's not just people who genuinely want to help Ukraine over there, but scum that just comes to fuck shit up and want to live their video game fantasies. No doubt there are a number of POS among the volunteers.

I distinctly remember a situation where American volunteers executed a surrendering, unarmed Russian soldier to the horror of the European volunteers in the group and leading to the rest of the Russians stopping their surrender and going out fighting instead: https://www.reddit.com/r/SubredditDrama/comments/10phb3z/rcombatfootage_believes_they_can_handle_the_truth/

There is a big difference in attitude that is taught between the American and European armies.