I don't think it's technically about "the houses all look the same." The exact same thing is also true of a row of traditional terraces, or London rows of townhouses, or Parisian apartment blocks, or even gorgeous structures like the Bath crescent. Each individual housing bit looks similar to all the others in all these as well.
Rather, I think the weirdness of UK new build housing estates comes from the fact that you've got all these ugly little block-like buildings (like Lego bricks) that are detached BUT not in a graceful way, like they would be in a traditional, spacious suburb, but all sort of jammed in (often at odd angles), with gardens all crammed up against each other. And they are usually located on the edge of cities, where it's just this depressing no-man's land - no nice shared public spaces, no cool little local pools of shops and cafes, no reason to stroll or wander or hang out outside.
Like, EITHER do suburbs properly (graceful buildings with nice spacious gardens and nice walkable streets and pavements, near local shops and services), OR if you want density, then do density properly (attractive apartment blocks with airy balconies and big communal gardens and shared green spaces nearby). UK new build estates aren't doing either of these styles properly.
I don't wander around them, but I do pass by them on the train, and I can hear Morrissey singing "The rain beats down/on a humdrum town/This town has got me down...." in my head every time I see one of these places.