You can’t compare dates with an = sign. The datetime object also includes the time down to the millisecond, I believe. You would have to be incredibly lucky to get them equal.
You could try to extract the date and a string for each object in 2 string variable and compare those.
In my case, I use the caldav binding with google calendar.
Scheduling for openHAB is a hot topic and is planned for a future update.
The devs are aware that this is a very often requested feature.
Regards