the description there

its also loli + furry porn.

loli hentai manga usually isn't construed as child porn because you could say they're 21, you can't prove it because they're drawings.

some countries have made it illegal, such as Ireland and New Zealand, but everywhere else it is either OK or 'not sure'.

so in answer to your question, hentai isn't illegal in the US, but getting lolicon hentai can get you charged with owning child pornography.. (but the law doesn't state anything on illustrated 'child' porn)