Of course, in some of these cases, the plural nouns would be appropriate in some contexts in standard English; but the context in which they are used in these data suggests it is not standard usage.
A few examples are:
I think it’s because of the infrastructuresOne question: should teachers worry about these tokens? We might note that stuffs occurs in the Corpus of Contemporary American English 463 times. Some of these are as verbs ('he stuffs his hands in his pockets'), but many are not. For example:
I don’t know much about their mythologies and all that
I have to help erm welcoming the guests and erm … helping carry stuffs around
it’s just that I don’t like jewelries in general
I’m just stay at home ... and just ... erm spent time with my families
so I was interested in doing speech therapies
lots and lots of stuffs ... I bought shoes, shirts, jeans, skirts, and other stuffs
so I don't want to go and find a hotel and all that stuffsSo maybe the plural stuffs is becoming acceptable even in America.
overwhelming centralization of all our food stuffs
I just have -- have to do stuffs after school
One way or another, plurals such as furnitures and informations seem to be very common in the Englishes spoken in such places as Brunei, Singapore, the Philippines, and India, and I suspect they will one day be the norm in most World Englishes, even if teachers continue to cling to traditional usage.