grammatical number - "This kind of things" vs "These kinds of thing"

I have a question about the following text:

Last week Alex Knapp at Forbes published an article criticizing my Nikola Tesla comic. I don't normally respond to these kinds of thing, but since it's' Forbes I figured a proper response was in order.

I would rather say "this kind of things" rather than the version in the text above.

Answer

Kind(s) of (like sort of, breed of, manner of, variety of, and so on) is slippery. It is usually interpreted as referring to the concept of something: uncountable, and taking a singular object. On the other hand, it can also refer to a set of them— or to a set of concepts— and the object would thus be plural.

I would expect to see

this kind of dog = one sub-type of the type of animal known as "dog"

these kinds of dog = multiple sub-types of the type of animal known as "dog"

these kinds of dogs = multiple sub-types of the multiple types of animal known as "dog"

and not so much

this kind of dogs

but I cannot ascribe this to any particular grammatical rule, only familiarity (in American English) and style. After all, in informal conversation we could ask

What kind of books do you like?

and expect a plural answer, as if you had asked

What kinds of book do you like?

which would sound stilted unless you were trying to make small talk with a librarian or bookbinder about classifications of books.

We also find similar constructions in more formal or archaic English, e.g.

uncommon is that sort of men that say in their heart, "There is no God." (tr. from St. Augustine of Hippo)

As an aside, I love TheOatmeal, but do not demand precise use of language from web comics.