So Al Qaeda had an internal disputes among leaders who then split off to form Islamic State (IS). IS began taking land in both Syria and Iraq all the while recruiting the vast factions of disorganized rebel groups fighting Bashar al Assad. They started growing in popularity because they've essentially become a reality TV show, popular on social media, free publicity, etc.
The US has started backing rebels in Syria to prevent them from needing to join Al Qaeda or IS. Russia comes in and says, "We want to help bomb IS", instead, they start bombing the US backed rebels, then apologized for "missing IS" and pulled out. Then sent in troops to help Assad more under the radar, training and whatnot.
So then, groups like Boko Haram (Nigeria) started pledging allegiance to IS because they also want to kick off their Hollywood careers. The US then started training Nigeria's military and Nigeria also purchased drones from China to have a new counterterrorism air campaign. Nigeria has been fucking up Boko Haram recently.
Back to IS, they have now set up a state-like entity with a fully functioning economy, school system, etc. like Hamas in the Gaza Strip, except, IS is much more sophisticated and holds oil reserves so they have a TON of money.
In northern Iraq, the Kurdish tribes have been the only group to really hold off IS. The Kurds use a lot of psychological warfare, such as, because IS believes if a woman kills you, you don't go to heaven, the Kurds have sent all women platoons out to hunt down IS. IS usually runs away when facing women.
Turkey and the Kurds have historically had huge problems. Turkey has also come under fire recently for allowing OS militants through their borders, possibly to have a better vantage point for attacking the Kurds. This is what's in question now.
So to answer your question, the bad guys in the Middle East are anybody carrying out attacks with a total disregard for civilian casualties. Civilian casualties happen in war, it's a fact. But blatant disregard for humanity is the moral divide here.
Edit: Many people are pointing out that I have left out the background information to the Saudi, Sunni v. Shiite, and Palestinian Israeli conflict aspects. You have to understand that some of these conflicts have 2,000 plus years of history and don't wish to open that can of worms.
Also, regarding an "American bias towards Russia", I'm speaking objectively. If you would like a biased spin, I could mention how Russia has lost strategic Naval bases in this conflict and because their polarized economy is tanking, they need to intervene for personal gain. But even that is fairly objective.
Also also, it's hard to get into all of this because I've written all of this from the toilet via my phone.
Edit 2: Also, if there are any Hollywood directors reading this right now, pm me if you want my input for making a female A-Team movie with Kurdish women fighting IS. I'd love to see Melissa McCarthy accidentally butt slam Abu Bakr al-Baghdadi into his goat mistress.
Thank you to whoever gave me gold. I'm glad you found my information useful.