As GigaGreg mentioned, Post to Host web hosts offer more quality control over who gets hosted. I've used instant activation-type free hosts before. They're a haven for spammers, so my sites & emails there were often banned by ISPs. Instant activation hosts also attract people who abuse server resources, and all the other sites on the server tend to load slowly because of this. Therefore instant activation hosts tend to be lower quality, even if they mean well.
As for removing accounts, there are periodic clean ups of inactive hosting accounts, which is why it would be a good idea to check the News & Announcements forum once in a while. Of course, contributing to the knowledge of the community through posts after you receive hosting reflects well on you & is always appreciated.