Europeans are very skeptical about backing businesses without a clear and short path to monetization, something that businesses like twitter or facebook did not have until very late. Maybe it's due to our history (lots of revolutions, lots of people going broke from one day to the next, etc) but people over here are much more conservative when evaluating potential investments.
Also, the whole data-mining / reselling business, which is "the backer of last resort" for most "free" startups in the States, is probably less developed over here (and is subject to fairly strict regulation).
It doesn't really have to be a short path. Sometimes things like highways and similar are intended to be profitable, but the up-front investments is so high, that the break-even point is far in the future. Sometimes the investments are clearly non-profitable monetarily -- like, say, regional public transportation.
The point is that the investment either has to be profitable within a predictable future, and then it's a business, or it must be significantly beneficial to the society as a whole, and then it's a state matter. I don't think this is universally recognized in EU (I think the OP confuses Europe with EU), of course, nor do I think nobody in US thinks that way, but general attitudes towards the statement that started this paragraph seem to differ.
The effect is that if you apply for e.g. any of the EU innovation funds, you actually have to come up with a business plan that states what are you doing, how is it similar to others, how and when are you going to ultimately turn profit. It's reasonable for VC to do the same.
Also, the whole data-mining / reselling business, which is "the backer of last resort" for most "free" startups in the States, is probably less developed over here (and is subject to fairly strict regulation).