Perhaps I’ll elaborate some more why I likened it to solipsism.
The way I see it, a typical crude, grotesque version of ‘social constructivism’ looks approximately like this:
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Everything is a social construct.
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Therefore, whatever bright idea my pug-faced friends and I came up with is the ultimate truth — because ‘truth’ is a ‘social construct’ too, so our little pug-faced company has socially constructed it, see?
The key difference to naive solipsism in the most blatant form is that, instead of a wordview with everything revolving around a single person, there’s an attempt to hide behind a ‘consensus’ in some pug-faced ‘group’, otherwise looks quite similar to me.
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Thus, you should shut up and bow down to our enlightened, progressive and so on idea, because ‘social constructivism’ reigns supreme, remember?
The motivation for it is not necessarily the aversion to status quo, as you put it, or something like it — how about some old things like power and money (speaking of progress in the human nature, by the way)? Nobody really cancelled the old ‘divide and conquer’ principle, and can you name many better ways to divide people than some of those ‘progressive’ theories? Besides, the concept of a scapegoat is still there, too, except instead of withes or heretics, you can hunt ‘X-ists’, where ‘X’ is from the same field as ‘social constructs’, ‘privileges’ and so on, you know…
Yeah, go on, travel somewhere to Russia, for example, and tell them about it, especially regarding a thousand (plus-minus) years of history before any kind of USA was a thing (there are older civilisations, of course, but since you wanted ‘white’, this’ll do, I suppose — besides, you’ll find not that many ‘whiter’ lands). 
Haven’t you suggested above that somebody move about a bit and not perceive the world as a carbon copy of their surroundings? I suppose I could return that suggestion to you mildly.
There are generally also so-called ‘quotas’ and so on — all according to ‘progressive’ theories we’ve discussed here.
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Are they, though? I was under the impression that they are a nearly unmoderated dump, unless something goes really wild and the community reacts to it somehow…
(Updated and edited a bit)