Isn't that what "free trial" means? If I am buying free trial, I would expect myself needing to manually cancel it if I am not happy
A free trial implies that you can use a service for a limited period without cost. It's only because they have normalised it that you expect to get charged if you forget.
As for the normalisation argument, if there's a common understanding that "free trial" means "X months free followed by being charged", then that's what free trial means.
Its only a common misunderstanding with these tech companies.
If I had a free trial with a sports club, or many other things, they will not charge me at the end of the trial. They will ask me if I want to join.
If I take a car for a trial drive, they won't bill me the entire price of a car if I forgot to mention explicitly that I don't want it after I return it.