You're trying to connect the dots between two separate phenomenons. This oversimplification will only mislead you.
You'd think that your left-wing instincts will guide you through this, but you will accidentally end up taking ugly sides in proxy wars in this part of the world.
PKK started out according to CIA's Operation Gladio to justify the 1980 coup, and continued operating in line with the Carter Doctrine. Its first actions were assassinating Kurdish and Turkish left-wing leaders (Zeki Ön, Mehmet Ongan, Adil Turan, Hasan Erkılıç to name a few).
Today, PKK follows the radical Islamist narratives (Şeyh Said, Seyit Rıza, etc. are often celebrated by them). PKK is in agreement with an Islamist terrorist organization (FETÖ) behind the 2016 coup attempt, whose leader (Fethullah Gülen) resides in the US. PKK conducts international drug trafficking at "cartel" scale (between Asia and Europe; ask your neighborhood drug dealer about it). PKK is backed by several crime syndicates and tribes who are responsible for countless human rights violations from systematic child/woman abuse to forced labour and human trafficking. PKK is currently taking part in the ethnic cleansing of Arabic, Turkish, Assyrian population in Syria and Iraq to make a space for an American-backed puppet state under "YPG" alias.
How is your IRA-PKK correlation shaping up now?
Your "reputable sources" are compilations of quotes by "usual suspects" anyway. Western organizations are not known for being the gold standard of social justice advocacy here, as they have a history of endorsing any "project" that fits their financial and political agenda; from cyanide process in gold mining, to civil warfare for carving up sovereign states.