I always insist on walking sticks in the overhead locker as per SOP (Standard Operating Procedures). I would have perhaps let you just leave it in the seat pocket depending on how big it was when folded up but generally there is no distinction in SOP between a walking stick and a folded up walking stick and so the crew member can't really be blamed for simply doing his/her job.
The quip she came back with could perhaps have been left out but I sympathise in that it is sometimes hard to bite your tongue when passengers try to negotiate, argue and retort when going about our safety related duties. I mean that in the nicest possible way and I'm sure, in this instance, you'd fit into 'trying to negotiate' rather than argue and being rude.
In an evacuation I honestly think that your stick would not have been of any use whatsoever. Past incidents have shown that evacuations can be very aggressive, particularly where smoke and fire is present, and it's my opinion that your stick would have been more of an hinderence. You sound mentally fit and strong which would probably do you more good in such a cirumstance.