There are questions over the legalities of wars in Syria and Iraq, but those regions were exceptionally volatile and conflict-ridden anyway. Just as a footnote, there are 250 mass graves in Iraq that are dating from 1979-2003, the time of Saddam's rule. I don't know how that can be blamed upon the West. Anyone who is of the Shiite faith or who is Kurdish will be glad that the world was rid of Saddam. As a hardline Sunni, Saddam did not view them as being Iraqi, so he felt that he could do with them what he wished.
Regardless of how you feel about Ukraine under its current rule, Iraq was a country where in a single year literally tens of thousands of kurds were killed using chemicals, and that is verified by independent human rights groups. I don't know how this can be compared to the situation in the Ukraine, which despite having problems with separatists, has nothing approaching that level of outright genocide of people on ethnic grounds.
Assad was arguably far worse than even Saddam. It was the world's responsibility to get rid of them and had the west done nothing, people still would have died unjustly. Again, this is not comparable to the situation in the Ukraine. Atrocities were happening in the region and would have gone on happening without intervention.
The Ukrainian conflict is an entirely different proposition and is about a hostile invading force taking over a peaceful country that has long been concerned for its safety since Soviet rule broke down.
I really don't think we do ourselves any favours by comparing like-for-like with ME wars. It merely fudges a very complex issue. In saying that, I do believe that opposition towards Western intervention often manifests as unwitting tacit support for blood-lust dictators, and their right to hold entire ethnic groups under their anvil.