there aren't enough genre-specific lists out there for country, R&B, etc. And, yah, even though "rock" is an all-encompassing term, at times there will be leanings toward that genre.
Entertainment Weekly has a 25 Best Rao Albums of All-Time list in the new edition, though. That could be added to the site. :)
I do not disagree with you but a way to answer this is perhaps that very few European artists play country or hip-hop, and most European critics have limited interest in these genres. Thus, from a US perspective the Acclaimed Music lists look too rock-oriented.
This is why I like the SINGLES-BASED form of lists: It helps to keep from over focusing on "album" oriented genres at the expense of great music from genres that are more focused on sharp 3-4 minute blasts of excellence...a.k.a. R&B/rap, dance music, most "girl groups" etc.
I love Dave Marsh's "Heart of Rock and Soul" for that reason (though I have huge disagreements with many o the 1001 he chose... )