...why do people like Stephen Hawking talk about things/events "before" the Big Bang? If time (as part of spacetime) was created with this event, it also marks the point in time that had no "before", doesn't it?
Caveat - only Physicists who know what they're talking about. Common clods like you and me need to be very careful about that.That's why physicists like to talk about things that happened before the big bang.
why do people like Stephen Hawking talk about things/events "before" the Big Bang?
doesn't that usage imply the assumption that normal physics prevailed during that process, i.e. that spacetime was "intact" enough to give a notion of a "before"?
There is no such thing.