The private property of the worker in his means of production is the foundation of small-scale industry, and small-scale industry is a necessary condition for the development of social production and of the free individuality of the worker himself. Of course, this mode of production also exists under slavery, serfdom and other situations of dependence. But it flourishes, unleashes the whole of its energy, attains its adequate classical form, only where the worker is the free proprietor of the conditions of his labour, and sets them in motion himself: where the peasant owns the land he cultivates, or the artisan owns the tool with which he is an accomplished performer.
This mode of production presupposes the fragmentation of holdings, and the dispersal of the other means of production. As it excludes the concentration of these means of production, so it also excludes co-operation, division of labour within each separate process of production, the social control and regulation of the forces of nature, and the free development of the productive forces of society. It is compatible only with a system of production and a society moving within narrow limits which are of natural origin. To perpetuate it would be, as Pecqueur rightly says, "to decree universal mediocrity."
I read this passage as saying that private property can be cool if you're Amish. There are plenty of things to say for being Amish, and Marx gets at this in his first paragraph. But what Marx is telling us is that we're not going to get Facebook and the iPhone and plenty of other things we like if we remain Amish.
Now, many people will rightly point out that modern civilization produces all kinds of awful things that Amish communities don't. The world isn't going to be destroyed because Amish people took a pass on electricity. The world could very well be destroyed because the same technological advances that begat iPhones are also producing weapons systems and genetically modified everythings.
People who believe it's simply hopeless to socially direct the work of those institutions from which something like the internet is born are going to end up taking a position against an awful lot of things that the average person likes and generally takes for granted. If they want to be persuasive, they will have to have a pretty good argument.
Marx is understood as taking a position on this by advocating communism, which is the democratic administration of all institutions, social and economic, in an advanced industrial context. I think part of this relates to his observation that many societies move past Amish-style living anyway, and once capitalist, they become violently expansionary and work perpetually to displace everything else by productive and technological advantage.
So on the one hand, this is what we have to contend with anyway, regardless of what we choose for ourselves.
On the other hand, Marx sees great possibilities in the idea that you could have things like iPhones and space exploration -- keeping the things we like -- while eliminating the socially destructive tendencies in capitalism that virtually everyone recognizes as undesirable, whether poverty, climate change, or war. I don't know if there is a primitivist argument that is analogous to this, but it seems to me that persuading people toward a saner management of what we already have by confronting what we don't like is going to be an easier sell than patiently explaining why all civilization must end.
Things to think about. Just don't take too long: the world can hardly wait!