You say we were not forced, but the truth is that we were forced to be under British rule and the British denied to let us choose a post colonial future for our island in a democratic way.
What they did to Cyprus was a divide and rule practice that was not unique. One of the principles of this divide and rule technique is: "aiding and promoting those who are willing to cooperate with the sovereign". Germans did something similar in Rwanda: "Germany used the strategy of divide and conquer by placing members of the already dominant Tutsi minority in positions of power."
https://en.wikipedia.org/wiki/Divide_and_ruleEven if there was never any Enosis or Taksim causes, the British could have achieved the same result by promising to the TCs greater powers if they cooperated with them. The TCs aren't interested just in excluding enosis, but they are also very much interested in having as much power as possible, and they don't mind cooperating with foreign powers in order to achieve this. So it is a classic case of divide and rule in my opinion.
What I am saying is at that time Greece and specifically Karamanlis wanted Makarios to sign the agreements, despite all of the flaws in them because he believed that was what was best for Greece. He wanted it to a degree that he, as I understand it, threatened to 'end Greece's support for Cyprus'. Makarios may have been many things but he was not stupid. As you have pointed out the threat of the British imposing recognised partition on Cyprus via say the McMillan plan was not the same as it's ability to do so, and Makarios would have known this. For me it is easy to imagine that the 'threats' from Karamanlis played as big or even greater role in convincing Makarios to sign the agreements than those from Britain.
Karamanlis was like our Cleredes, so pro-American that they thought that whatever the British and Americans advice was in our best interests. He is the one who said "Greece belongs to the West". Still, it is one thing to threaten "I will stop supporting you" and a whole another thing to threaten "I will ethnically cleanse you".