"Further, if you see a word in print, how the hell else are you supposed to pronounce it?"
Well the most interesting way is to ask on the Mudcat, of course. Or for those who are shy, spend five minutes with a search engine and you'll always come up with the goods.
Before the internet, of course, there have been dictionaries which provide pretty good information on that kind of thing.
It seems to me that, when you learn a name from someone who has that name, you accept their pronunciation, even if it's different from the way other people might say it -it's a folk variant. But when you learn it from print, I think there's a duty to make some effort to find out how it's pronounced in the community it comes from. Good manners.
Especially if you are giving it as name to a child who is going to have to live with it, and who might find themselves really brought down say on a trip to Ireland when they find the way they think their "Irish" name sounds is nothing like the way anyone in Ireland would pronounce it.
One lad whose name always sets me wondering is the Yorkshire born actor Sean Bean (Boromir). What were his parents thinking of? And how did they pronounce those names?