They don't, they have a right to attack all the russian ships they want, attacking another country's ships isn't right,
Big "if a bully is mean go tell the teacher" vibes right here.
Fuck off. If someone is aiding someone attacking my people and catches a few fuckin strays seems like it's their problem huh?
What you're not understanding is something every other country including Iran understands.
When you sell military arms, tied to an unfolding conflict, you're taking a risk.