I think you've missed one point in my post.
I was suggesting a slightly different hypothetical situation.
Here it is spelled out in detail:
A - SB, 5K
B - BB, 10K
C - fold
D - limp 10K
E - All In 14K
F - limp 14K
G - fold
H - All In 21K
I - Button, limp 21K
OK, maybe if I said 'Call' rather than 'limp', this would have been more obvious.
At any rate, In this situation, All early players, A, B or D can raise. However, if they either fold or call, F can only fold or call.
Obviously, no matter what else happened, the blinds have the option to re-raise.
While all limpers already had a chance to raise, even if the blinds only call, player D is facing a full raise, which opened the option to him to re-raise.
If it's still 21K when it gets to F, he is only facing a partial raise of his 14K call, so he isn't entitled to re-raise.
Bottom line, even if there were several partial raises, when action returns to a player, if the combined raise they have to call is less than one BB, then their only option is to call or fold.