Answer:
because he didn't mean to create a separate church, but rather reform the existing Catholic Church from within.
As the movement grew, it led to a split in the church, with followers of Luther and other reformers breaking away to form new denominations. This caused a great deal of upheaval and conflict within the church, and Luther himself came to regret the division and strife that resulted. In particular, he was troubled by the violence and persecution that occurred as a result of the religious conflict, and he continued to hope for reconciliation between the various Christian factions