It is true that Turkey was a part of the Korea conflict. But back then, it was a country still influenced by Mustafa Kemal, which was stongly secular and one of the great leaders of the time (he still would be one, had he been alive today!).
Since then, there has been a couple of coups, the invasion of Cyprus, amongst other things, like attacking kurdish organizations who were fighting against ISIS. Even some quiet support of ISIS, if one is to beleive certain sources (like members of the US congress).
There is also jailing of critical journalists, and of political opponents (the mayor of Istanbul was a high-profile one example, recently). The beating of protesters at a Turkish state visit to the US is another example. So, ever since Atatürk, Turkey has changed. It is, sadly, not the same nation as it was back then.

Neither is NATO the same organization as it was back then. At that time, it was to work against communism and the Soviet Union. Communism is gone, so is the Soviet Union. NATO has become a organization which promotes democracy and freedom more than one to combat communism at all costs.

Still, it has the right to veto, as it still is a member. Though, I wonder how many of the current members would have been let in by Turkey now, if they hadn't been members already?

I used to be all for a NATO membership. But if it means supporting Erdogan, changing our constitution, having political courts and having no free speech, we would only remake ourselves in the image of Erdogan. Then it is not worth it. We will then instead strengthen our defenses on our own, and if we then die alone in the defence of freedom, so be it. It is preferable to being under the thumb of a pseudo-dictator, or real dictator, of any nation.

It went something like that, during WWII Russia suffered big losses when attacking Finland and in order to focus their efforts somewhere else Russia proposed a neutrality pack with Finland and other Scandinavian countries (unsure about this part). So Finland become a neutral country in exchange for Russia pulling their military and taking a piece of their land. They want to join NATO because they do not trust Russia to honour their agreement towards them and are seeking a protection kind of thing which all in all is beneficial for NATO countries as it puts even more landmass between core members and Russia. I hope this makes sense and should be accurate enough information for you to look into it further if you are interested.

Romania, Bulgaria and North Macedonia are all members of NATO. You are confusing it with the schengen zone. Turkey needs to be kicked out of NATO.