There's actually a really great explanation for this phenomenon, and here's a few links to some excellent articles that I just found very compelling:

The volume wars

And this one which I haven\'t read yet

The second article seemed too long for me to read as I was so tired last night, but will read it soon I guess. Basically what they speak of is how people who do mastering or producing are so ill over these idiot/ignorant "artists" who tell them to always make sure that the album is LOUD !

Making the master "hot", is responsible for all sorts of audible atrocities such as say, clipping, really severe compression etc.. The thing about vinyl is that you absolutely can not compress the frequencies like you can with a digital press.

This results in much better dynamics, a full frequency range being able to come through and be reproduced by your wonderful gear. But I'm not doing the explanation any justice, just read the articles.

Lastly, a short youtube video of an example:

Soundwars clip

Doug