I think VOO is a US-listed ETF. This makes it somewhat difficult to access for a European investor. Basically, most of the large US stockbrokers (Schwab/Firstrade etc) won't allow an EU citizen to purchase US-listed ETFs. There are some smaller US brokers who will, I believe, allow such purchases.
I'm not familiar with the other ETFs you mention, but I would imagine they may well fall in yo the same category.
Hope this is of some help.
I think it is illegal to sell US ETFs to European investors unless they provide the necessary documentation and none of them can be bothered to provide it as presumably they consider the market too small for the effort involved in producing more documentation