I had a friend write this on Facebook in reply to someone, and this got me thinking. I feel like this argument will lead to no where because it would be a double standard as some will accept it as valid for one argument, yet deny it in another.
I guess it would stand or fall based on what is meant by "not biblical".
I've seen people (usually on internet message boards) take a stand against something or other they personally dislike and how we shouldn't be doing it. Whether the subject at hand is drinking, smoking, rock music, tattoos, whatever, the rallying call is that "we are not to be like the world". But apparently it's OK to "be like the world" in using the internet, wearing clothes, going to work, drinking tea and coffee, and doing whatever they happen to like doing.
The argument that we shouldn't do something because it isn't mentioned in the Bible is equally silly. Some things are Scripturally mandated (e.g. love God). Some things are Scripturally prohibited (e.g. thou shalt not commit adultery). Many other things can be figured out based on Scriptural principles (e.g. the Bible doesn't explicitly say we shouldn't perpetrate a 419 scam, doesn't explicitly say we shouldn't watch porn on the internet and doesn't explicitly say we shouldn't spike someone's drink, but I think anyone would struggle to argue doing such things aligned with Scriptural principles. The remainder of things fall into areas where the Bible is silent, so in the absence of clear instruction one way or the other I'd say we get to choose for ourselves.
If "not biblical" means that the Bible doesn't explicitly tell me that I'm allowed to wear a blue shirt with green pants on a Thursday then it's true to say that "not biblical" doesn't mean "not okay".
If "not biblical" means that the Bible prohibits adultery but in this day and age it's pretty much accepted (if not expected) then "not biblical" still very much means "not okay".