Is it really unwise to buy a car that has been in an accident?

The only unwise decision you can make is to make a decision with out all of the necessary information. Where was it hit? How long ago? What work was done? How does the car run? Frame damage? Clean title? Paintwork? Why are the selling it?......

Yes, it is, as you put it, "unwise"- there are millions of cars out there- why buy a wreck? because you are trying to save money? no one rides for free, and if you buy a wrecked car, it can be unsafe and expensive- this is kinda a no brainer-