The use of the word "Those" (which is a demonstrative adjective) doesn't change whether the sentence means "Then AND Than" or "Then OR Than" it simply shows which noun you are referencing. Those is a plural demonstrative adjective, which means it is used when the noun in question (in this case "words") is plural. The singular form is this or that, and would be used if talking about a single word, which isn't the case here. Vegas wanted to be able to use mistakes with the word Then OR Than which is why he used "2 words", Searles contest the sentence means Than AND Then. The word "Those" simply explains which noun in the sentence we are talking about (in this case the words This and Then) because without it we don't really know what the two words in question are.
***I'd actually argue that the proper word here is "these" as it also relates to proximity of the noun your are talking about (you say: these cookies here, not those cookies here).***