Umm, Dex? This looks like you’re replyng to *my *post. 
Maybe because it points out that the word is meant to be used only in the singular? 
If it is an English word, it is still an English word that is singular in the form “kudos.”
If it is used as a plural, for the singular “kudo” it is only used that way because ignorant people have done so. Much the same way that ignorant people not only used the improper contraction of “amn’t”, but used it in improper constructions, like “I ain’t …”
Now, you can, if you wish, choose to join the ignorant masses. I have preferred, in my life, to avoid joining them when possible. Part of the point of this message board, you know? 
I must correct myself here, having misread the post. I was using it in the common English usage, but not as a plural of kudo. I was usng it in the sense “honor,” or “award,” or “acknowledgement of acomplishment.”
I’ll ask D.S. Young again. What d you suggest as the plural of kudos?
In that artilce, Dex said “Incidentally, kudos is singular, meaning honour, fame, or glory. If you hear someone say, “I give a kudo to so and so” (Dr. Laura did this the other day)–now that’s clueless.” Thus many argue that “Kudos” is a singular English word that ends in a “s”.
Thus, when Contrapuntal posted “Blast. I really did not think there was a real answer to my smartass question. Kudos.” he was using it correctly. And, in my example "Thus “kudos” is perfectly correct, much like “congratulations”, the word was also used correctly.
If he had posted “kudo”, you might have an argument. But as Colibri quoted Merriam-Webster above, even “kudo” is now an accepable usage.