Blogger is notorious for "reimplementing the web experience". Just try opening a Blogger page on an iOS device. You'll get an empty page, then spinning gears, then after a while the page will finally land. Then you'll have a page which won't scroll properly. Because someone just had to reimplement scrolling. Better.

Let's take the horrible Onswipe themes as another example. They not only break functionality and make the page slower, but also break zooming in and show buttons that pretend to be iOS buttons, but aren't.

I could rant about this for hours. It's all the same basic problem: people trying to redefine/hijack basic browsing functionality. I interpret this as extreme hubris ("I know how to design this better!") or arrogance ("this is how you will view my site, period!").