Lets say,YPG is a new formation and nobody knows about it (being consisted of PKK militants)
However,PKK is in the list of terrorist organizations of UN.So it would be direct confrontation to not just Turkey,but also general understanding of terrorism of the world.Then,everybody would have their own "terrorists"
Actually it is quite correct from perspectives of every individual country,now we conduct operations with whom being called terrorists by Assad, so does Assad the same with YPG.
However,at least Russia had better not mention PKK as "any other organization" while they recognised terrorists by UN.
At least our terrorists are not in the lists of UN yet
PKK is not on UN terror list. It is on US terror list yes, but for obvious reasons, 60% of the UNSC permanent members do not consider the PKK a terrorist organization.
YPG however is a unlawful combatant group as far as the Syrian Arab Republic. Everything that happens between Syria and YPG is out of necessity not legal precedent.
While the Turkish support, training and arming of groups close of AQ and Even AQ in Syria is done on state level with embeds and...as we saw lately with the formation of a parallel police force which isn't an arm of the Sovereign state of Syria.
Basically, Turkey is preparing a vassal entity in Syria.
No country wants a neighbor having undesired rulers or governments or ambitions.This is the same reason for Russia to intervene Georgia and Ukraine.You know better than me.
As for Turkey, we had a pact with Syria-Jordan and Lebanon for common trade and travel policy during pre-war period.Although Assad was in the head of Syria,this treaty was signed.
However,with the initial protests spread, Assad has chosen to be part of Iranian politics, which made everything into rubbish.Of course,Turkey is a relatively strong country in MidEast, and would have its own sphere of influence.And Syria is among the target countries.
When it comes to AQ, Turkey forced northern AQ elements to leave the area,and they did.(Azaz-Marea region)
AQ is unwanted element for Turkey,because they screw up wherever they involve.And for them,those who fight with Turkey are fasiq (those fallen into falseness) and there should be no cooperation with them.
Undesired? Did Russia depose Saakashvili when Georgia attacked Ossetia? Did Russia depose Poroshenko when they invervened in Donbass, did they depose Turchinov & friends when they intervened in Crimea? Did the Russians depose any leader in their interventions lately, including in Chechnya? Russians even agreed to call an end to war they could have easily won with more bloodshed, but instead they let Chechnya go into chaos.
Assad has always been part of the Iranian politics, it were Syrian missiles that were used by Hizb'Allah against Israel. Assad was the one that was using Iranian crude for its refineries and making a killing on them. It was Assad that would buy a lot of dual use technologies and pass them to Iran. Metis-M ATGM's that Iran reversed were also bought by Syria.
Turkey forced what? Turkey trucked whole buses of Al Nusrah and affiliates on both side of the border to help with Aleppo counter-offensive. Turkish weapons, ammo, PPE, Supplies, maps and even equipment was captured. Turkey even made recon flights, used artillery in support of Al Nusra very early in the conflict.
Yeah no cooperation with them, only tons of East German AKM's that Turkey got after the end of the Cold war from Germany, found out their way into Al Nusra and funny thing this, not later than in January the "police" in Norther Syria has the same guns Turkey send to Nusra. Well how come?
Drop the argument, Turkey is partaking in a regime change plan, while it almost suffered a regime change itself. Better watch out who you sleep with.