It's not "some" sites, it's nearly all. Heck I picked the front page of BBC News and opened it up. Wall of minified JS. Further down the page we see something

It's not "some" sites, it's nearly all. Heck I picked the front page of BBC News and opened it up. Wall of minified JS. Further down the page we see something that vaguely resembles normal HTML except for stuff like this: <div id=markets_index_promo class="hidden" data-comp-meta="{"id":"markets_index_promo","type":"remote-portlet","handler":"remotePortlet","deviceGroups":null,"opts":{"assetId":"10263779","id":"market_data\/markets_index_promo","loading_strategy":"post_load","position_info":{"instanceNo":1,"positionInRegion":3,"lastInRegion":false,"lastOnPage":false,"column":"secondary_column"}}}">