I don't like how this question is worded. I think having a method to "cure" any problem would likely be more helpful to have than not, and I would support it being developed. The part of the question is dislike is how it's phrased at the end. I would never want anything like this to be mandatory, and would never support governments attempting to make it this way.
For something like a couple being told they will never have a baby, then managing to have one, I can see why the parents may want their son to grow up heterosexual, in order to continue the family name, especially in a "only son of an only son" scenario. (Remember, if you have no children, you break a previously unbroken line of descent from the very first human coupling)
As for people complaining about how it's not a free choice, I don't know about that - if I offered you the chance for an eternity of bliss after death in exchange for you being a slave for 10 years with no memory of anything before your slavery term started and you agreed to it, do you think the slave you would feel like you had had a choice? Obviously not, why would someone become a slave willingly? If you don't know there was a choice made beforehand, you don't know it was your choice. [THIS LAST PART IS ONLY IF THE "CURE" WORKS BEFORE BIRTH]
If it's made available and works at any stage of life hell why not, then we could put an end to all this "if you saw life through my eyes" stuff between homophobes and homophobe-a-phobes(this isn't really a word, but you all know what I mean) being able to swap sexuality