What's not clear-cut tho is "who is a PKK member", because you know, terrorist organisations don't have very well organised membership program and an audit.
In Turkey, anyone can be a terrorist. There's even this legal concept of "aiding terrorist organisation without being member of it" and aid can be something simple as writing article which support their cause and the "supporting their cause" definition often can be very broad too because you might be accused of supporting a terrorist organisation due to something like advocating for the right of learning the mother thong in schools. You can easily go to jail for supporting something like that if the Kurdish political movement demands it too(terrorists want it, if you want it too then you are helping the terrorists).
All the issues arise due to the difference of terror definitions between Turkey and more liberal countries. In Sweden you can march with the poster of Abdullah Ocalan, the founder of the terrorist organisation and in Turkey you might be accused of supporting terrorist if you say Mr. Ocalan by mistake(you are expected to parrot something like "baby killer" or at least "head terrorist").
Another problem with the Turkish stance is that it's inconsistent. This terrorist organisation is not formed in a vacuum, it is a response to oppression on the Kurds by the Turkish state and the politicians can dial down the terrorist accusation and talk about "Making mothers stop crying and discussing the issues and finding a violence-free solution" if it fits their current political position.
10 Years ago Erdogan was the champion of the Kurdish rights(the original oppressors are the secular nationalists, in an attempt of nation building. They oppressed islamist too, so at that time Erdogan was a freedom fighter) and was on a brink of Good Friday like resolution on the issue when fractions of the opposition said that he was a traitor and terror supporter. Today the roles are completely reversed, Erdogan is the hardcore nationalist and the opposition wants a resolution and dialog on the Kurdish issues and the PKK associated but pacifist political movement supports the opposition, which is probably why Erdogan is against "Sweden joining NATO unless gives us the PKK terrorists". The elections are in less than a month, Sweden will most likely join NATO once they are no longer useful to the Erdogan's propaganda or the opposition wins the elections.
I hope Sweden never bows to the Turkish demands because that would mean reducing the Swedish freedoms of speech to Turkish level and I promise you, the Turkish freedom of speech sucks.