Hi!
I’m sorry this has caused confusion – though I’m not quite sure what you mean when you refer to the unusual activation procedure. In general, you must have The Events Calendar installed and activated as a prerequisite (because Events Calendar PRO operates as an extension of that plugin, rather than as a standalone plugin).
So long as that’s in place, you should indeed be able to upload and activate Events Calendar PRO like any other plugin.
Does that help at all / are you still experiencing difficulties here?