1)
Why does it say "Gomelim Aleinu"?
1.
Malbim: This is a great injustice, to expel us after we did not harm them, so we ask You to judge this case!
2)
Why is it called Yerushasecha Asher Horashtanu?
1.
'Rashi': You Yourself did so - they have no claim against us!
