The bat ponies recount how they indeed saw you stamping all over
their precious moonflowers, your face contorted in an expression of wicked glee.
This does sound pretty convincing… You proceed to tell the bat ponies the completely plausible story of how you just woke up one day and the moonflower was totally already there.
The bat ponies will not be swayed by your lies!
They witnessed you destroy their garden! Okay, that’s just not fair. You’re friendshipping the best you can!
Why are they so mad at you?
In answer, the bat ponies point you towards what appears to be
the badly-mangled remains of a moonflower plot. What, they don’t think
that you did this, do they? You friendship as hard as you possibly can
IT’S NOT WORKING The bat ponies finally let you up, and graciously allow you a moment to replace
your Cartographer’s Cap upon your noggin. Thus prepared, you greet them
warmly and beseech them to form a bond of friendship with you.
They do not look impressed. In fact, they look kind of angry. 
