Vines slow you down when flown through in spectator mode. They also slow you down when flown through in creative mode, but that makes sense. However, in spectator mode you cannot interact with any blocks. You should not be slowed down with vines. I assume this happens with ladders too but I can't test because my game crashes when I place one.
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trazlander
migrated
Vines and ladders no longer slow you in spectator mode, but why not also add this to creative mode? It's quite annoying to get around in creative mode when you can't use shift to go down if there's a lot of vines around, or you're in a jungle, or you're flying your way through a keep with lots of laddery passages.
The bug report for this is here: MC-5410 "In Creative, flying down is stopped when brushing up against ladders or vines."