While I agree that it shouldn't be automatically assumed that someone who has bitcoins to spend will use them for illegal purposes, I'm curious as to what specific hurdles you encountered as mentioned in your post?

In my country at least, if you want to purchase something online and in a different currency than your account and CC's denomination, the conversion is done automatically for you at checkout, at whatever the bank has set for the rate, usually a fair one. Works like this regardless of what store you buy from, could be in the U.S, Europe or somewhere else on the globe.