Earlier quoted context omitted.
You can . You wouldn't find buyers or renters without discounts far exceeding the cost savings, because it's seen as substandard, however. If anything, even places where space is extremely costly, one clear way of judging relative luxury level is the ratio of bathrooms to bedrooms.
"Substandard" is not the complement of "luxury". And nobody is saying that middle class people won't pay the extra cost of private bathrooms, clearly they are doing that. The point under discussion is if it's inhumane to give poor people free housing where they have to live like European middle class students and share bathrooms, and the answer is a very clear "no, it's not inhumane".
EDIT: In fact, many places you'd struggle to even get approval for places with communal bathrooms without special exemptions, as it's so far below expected standards that these expectations now often violate government set standards as it's come to be seen as entirely unacceptable to impose it on anyone. E.g. in Norway, the standard rules for a permanent dwelling requires a bathroom with few exceptions, and sets minimum requirements for the size of the bathroom.