An event is a geocache in the world of geocaching. Therefore I do not see any reason to not include those. I am quite sure there would be more complaints/bug reports if it was changed towards the suggested behaviour.
As many knows, the Profile stats is a copy of the open sourced FindStatGen. FindStatGen has the exact same behaviour for this particular number.
My personal opinion is that it is correct as it is now, and that I would be confused if it didn't count events. Overall I would say the specific number is quite uninteresting regardless actually. It's not that I have ever used the number for anything.
Also, comparing it with the fact that events aren't calculated into "archived caches" is in my opinion wrong. Events are supposed to be archived, physical caches are not supposed to. But yes, technically it would be no problem to make such change.
We do have hopes for "plugins" in the Profile stats in the future. If it happens or in what degree I do not know today.