It is legal jargon that gives them the right to do that, but it also gives them a lot of other rights. If they only wanted to display the PDF back to you, they could affect that meaning very easily.
Not using phrasing thst has already been tested in court is easy, but fraught. If someone sues you because of a reasonable thing you did to display a document and you have this phrasing. It's open and shut because someone else has already litigated it and so there's legal precedent. If you use different phrasing and someone sues you, there's a greater chance you'll have an actual drawn out court case to convince a judge that your phrasing means what you wanted it to mean. Remember, the meaning of words and phrases in a legal context can differ almost arbitrarily from what they mean in a conversational one.
As a business owner that just wants to get on and provide a service that displays a pdf you got sent, which do you go with, the one that lets your resources go to providing the service you intend to provide, or the one where there's a greater chance your resources will get tied up in a legal battle for the sake of making the terms almost no-one reads anyway a little nicer?
though maybe true bad actors would try harder to pretend being a company with some humans involved, rather than this openly anonymous site.