Regarding 'jargon': this word has a number of meanings. and I think it might be helpful to distinguish these, because some of them are more pejorative than others.

I agree with Steve that within a specialised field, certain words will function as a sort of shorthand. You need to do the background work, or at least some research, to discover what the technical or theoretical significance of these words are. This is an example of one definition of 'jargon'.

But the word can also mean both pretentious, unnecessary and disliked uses of vocabulary and expressions and, by extension I suppose, nonsense.

I think that there are sometimes cases where a person who does not understand specialised vocabulary dismisses it as jargon more or less because they do not understand it. It's easier to say 'this is nonsense' or 'this is pretentious' or even 'I think people use language like this to cover up their stupidity rather than to display their intelligence' than it is to make the admission 'I don't understand it'.