Fair point, although I think that is a function of society becoming less formal. For instance, much of the lingo in the trades (historically less formal) is purposely slightly vulgar. For example, first thing that comes to mind is male/female terminology for things like sockets & connectors. The terminology only makes sense if one considers it in a vulgar context, and it isn't a recent usage (I've seen repair manuals from the early 20s that use this terminology).
What may make it seem to be changing is that society (or more particularly, white-collar workers & pop culture) has gotten far less formal than it used to be. Even non-tech companies are moving away from suits as required office attire, the only professionals I know personally who still wear suits to the office are lawyers or in the financial industry (which have always had a conservative, slow to change reputation).
Entertainment media's driven a lot of it, I think, for whatever reason. Generations X and Y have tended to make catching accidental (and not even especially interesting) double entendres a prominent feature of the humor-media they've (we've) created in a way it wasn't (yes, some, but not so constantly) before. Earliest example I can think of that did a lot of this is Beavis & Butthead, but it's been all over the place since then. I'm not sure reduced formality's behind the presence of so much of that in media, all of the sudden.
After articulating your point more, I'll definitely agree with that. Shakespeare was all about the double entendre, but cleverly writing double meaning into a turn of phrase is definitely different from forcing it into anything that would apply. Still haven't looked into the history of the naming of 'finger', but it's 100% possible that it wasn't intended to be sexual.
In a way, it cheapens the phrase 'double entendre', as AFAIK the phrase used to imply a clever, sometimes obscure, double meaning that was intentional vs. anything that could be taken out of context.
What may make it seem to be changing is that society (or more particularly, white-collar workers & pop culture) has gotten far less formal than it used to be. Even non-tech companies are moving away from suits as required office attire, the only professionals I know personally who still wear suits to the office are lawyers or in the financial industry (which have always had a conservative, slow to change reputation).
Edit: typos & formatting