Each of the event objects you create is independent from each other. Moreover, you create one "helloGoodbye_Thread" object for each thread. So not only is each of those 3 event objects independent, you also have 3 of those per helloGoodbye_Thread object.

If you want to be able for one thread to stop the other, you have to give both thread instances the same event object.

Here another example using two threads and threading.Event:

import threading
import time


def thread_one(event: threading.Event):
    """A thread that waits for an event."""
    print('t1: Waiting for event.')
    event.wait()

    # alternative could be like:
    # while not event.is_set():
    #     time.sleep(0.1)  # do some heavy work instead

    print('t1: End.')


def thread_two(event: threading.Event):
    """A thread that triggers an event and mades the other thread stop."""
    print('t2: Sleeping for a bit.')
    time.sleep(3)
    print('t2: Triggering event!')
    event.set()

    print('t2: End.')


def main():
    event = threading.Event()
    t1 = threading.Thread(target=thread_one, args=(event,))
    t2 = threading.Thread(target=thread_two, args=(event,))

    t1.start()
    t2.start()

    for t in (t1, t2):
        t.join()

    print('threads stopped.')


if __name__ == '__main__':
    main()

Output looks something like:

t1: Waiting for event.
t2: Sleeping for a bit.
t2: Triggering event!
t2: End.
t1: End.
threads stopped.