Yes, both Iran and the Saudi Kingdom are barbaric and we know that. The difference, however, between their barbarism and the barbarism of the US, the British, the French, etc. is that Western modern babarism is carried out "democratically": there are meetings, debates and voting before deciding on the actions (invasions, occupations, air-strikes...), which, by the way, directly and indirectly, kill, maim, displace, etc far more people. One figure comes to mind: half a million Iraqi children killed by sanctions.
When they do it, it is barbarism and terrorism. When we do it, it is protecting "our way of life" because they are against freedom" and "democracy". Some people are exempt from being called barbaric and terrorists because they are our friends, they buy weapons from us, we helped them establish their Kingdom, they put money in our banks, they keep pumping enough oil which help us maintain "our way of life".
“We attacked a foreign people and treated them like rebels. As you know, it's all right to treat barbarians barbarically. It's the desire to be barbaric that makes governments call their enemies barbarians.” — Bertolt Brecht