Quesry about Events calendar and notification (Possible bug)

Hello all,

Our sales team use Lead doctype, talk to lead and update the discussion as Event in this fashion. (with current date time)

Now at the same time they create another Event for future event that needs to be done.
For ex. The following client wanted to postpone their plan for next year. So, last year (on 2023-Aug 30) one of our sales team had created an event for today (for 1 year later).
This is how the event was displayed in Lead.

The detail about the event is as shown:


So, today, all of our employees (who do not have access to lead, team from accounts, management, field staff, everyone active) get a email reminder for this event.

We thought this was because the event was set to Public. We tried creating dummy events (private) and tested. Everyone is still getting emails.

Was this designed like this ?
What is the use of Tasks and Events in Lead ?

I understand creating public events to notify all employees is a great feature but I also think there should be a way to limit who gets emails.