The 'I suggested yoga' but of the OP made it very clear what kind of thread this will be.
Anyone who thinks it's fine to behave in such an odd way isn't going to listen to anyone else.
Why on earth would you think it's ok to refuse gymnastics lessons on the basis that, err, why exactly? Oh yes, on the basis that she wants to do it, and suggests yoga instead, because err, why exactly? Oh yes, because she doesn't want to do it as much.
What is the logic there, and as for defending it as 'well, I'm paying', personally I think that doesn't really stand up to scrutiny. It would if tour DD wanted to start gymnastics and you said you can't or won't pay... but this snidey 'I suggested yoga' nonsence seems to mean you'll pay but only if it's something that you've preapproved, on the basis that she doesn't want to do it so much... well, it's all a bit weird.
Bit then I wonder, what kind of poster decides that clear references to a previous posters thread means 'lots of other people must agree with me then'? Clearly that's not the situation and deliberately twisting it to get to that frankly extraordinary conclusion, well, it shows how this thread will go.