This may seem strange if you come from the commercial web, but on independent web, it's a pretty common sentiment. There is very little benefit to actually getting visitors from the outside if you have no interactivity and no ads. It's not that they attempt to keep visitors away, they just don't do much to bring them in. Blocking commercial web crawlers isn't particularly rare, for example. Some don't support HTTPS, which means you won't get listed on Google.