The first sentence focuses on the 'you' as the purpose of the fight. 'you' becomes the primary subject.
The second sentence focuses on the 'we' as the primary subject and offers the purpose as an objective.
The difference is in the focus of the statement and depends on the purpose of making the statement.
Hope this helps,
Thanks a lot Deanna,
Wouldn't you say that in
2-We are fighting so that you can be free.
we are actually engaged in an activity that would be considered as a fight as such, but in
1-We are fighting for you to be free.
the nature of the 'fight' is less clear?
3-We are fighting for you to have a good educational system.
4-We are fighting so that you may have a good educational system.
Isn't 4 a bit strange here?
The 'fight' here is not truly a fight. The term has been used metaphorically. I think the metaphorical use of the word 'fight' doesn't fit well in 4. But I am not sure at all or else I wouldn't ask.