Whenever a question I've voted to close pops up here, I feel the need to explain my vote. I hope it helps. I also hope it's not insulting.
With a small amount of research, you could have found that delight never had anything to do with light, so de-light isn't really applicable. Hence Closed.
Delight is a recent spelling of a much older word, delite, crossing over from delite to delight in the 16c. when other "-ight" words became prominent: light, flight, and others.
It comes from Latin, dē (intensive pref) + lectāre (to entice) so, delectare meant to entice a lot. We get words like Old French delectable, from Latin delectabilis "delightful"; also delectably, delicious, and others. If any of those carry a negative connotation, feel free to jump in (that's basically what your question asks).
All this could have been found in one of our top recommended sources, etymology online (or etymonline). The recommendation to look in etymonline come from this post: What are your favorite English language tools?.
If I can do this in about 1 minute, so can you! What if every body asked us a question on one of the millions of words which could easily be found in a decent source? We would be slaves if we had to answer them all, and I don't like being a slave to someone who can't even find a rudimentary explanation. If someone, however, makes an effort, I up vote their question and sometimes answer, but I don't close (unless it has another problem, which can be found in out site tour and help section).
Why couldn't I give all this as an answer? Takes too long. I'd rather answer better questions.
In my real life, people ask me question after question after question, and I am truly happy to answer, because the answers aren't readily available. I'm pretty much a professional question answerer. (Aren't most of us to one extent or another?)
This is fun, but it's not my real life. We have to prevent user burnout by screening the questions.
The number of words in the English language is: 1,025,109.8. This is the estimate by the Global Language Monitor on January 1, 2014. That represents a lot of answers.