...that even from what I am about to say below, I still sympathize greatly with you. They should have at least offered you a stipend of some kind (~100-200) for the hassle- especially the appointment/lost time(!)
All that said, I actually understand why they need to stand firm with this issue. There's no way they can completely hermetically seal up an HDTV. It's just not possible, nor is it possible to control each and every environment the HDTVs pass through before they arrive in our homes.
There's simply no definitive answer whether or not the bug was there already or was not.
Ditto for certain types of post-delivery screen cracks. I have unfortunately experienced this with new HDTVs in the past
. Basically, it reasonable to assume that there has to be a line after which the responsibility falls wholly onto the owner for certain types of things, which could include insects inside.
More importantly though, what quotes have you received from third parties regarding the cost/time to repair?
How on earth can't this be covered and why is Samsung Customer Support so awful?
I purchased a brand new 55" inch TV 4K SUHD Smart TV five months ago at Best Buy for about $1300. I came downstairs about a month ago and turned it on and there was a tiny dead little fruit fly or some type of tiny insect in almost the dead center of the screen. I figured I could call Samsung and they would either replace the TV or send someone out to fix it.
The first person I got told me it was not under warranty so I asked to speak to her supervisor. She hung up on me. I called back and got a different person obviously who said yes it is under warranty and we will set up an appointment for someone to come out to yoru house. They set up the appointment. My wife took the day off from work and waited for the guy who never showed up. I called Samsung and they told me the appointment was cancelled. I said I didn't cancel it nor did my wife so I am not sure you can cancel my appointment without me or my wife approving that. They couldn't tell me who cancelled it.
They set up a second appointment and asked that the TV be taken down off the wall because the server technician won't take it down. My wife took a second day off from work for this. The technician came out and took pictures (it gets worse) then left. Obviously I can take a friggen picture with the thing on the wall and send it via email to anyone who asked. The technician said if you don't hear back in a day or two call us. I figured I will even give him a few more days and called a week and a half later. The store told me to call Samsung directly.
I called Samsung directly and they said no a fly in screen is not covered. We don't cover rodent or insect infestations. I was pissed that they would insuate that I had an insect infestation or rodent infestation. I told them my house is spotless and they can come over at anytime for dinner to prove it. If my house was infested with bugs I would think I would have fifty in the screen!!!!
I asked to speak to a manager. The manager came on and said let me see what I can do and hung up on me. I had to call back and push it up the chain again. Finally I got someone from "Executive Management" on the phone which means they got John Smith from the back room to try to shoe me away obviously.
I asked is it normal for a Samsung TV to have a small tiny bug to end up in the middle of the screen. He told me no it is not but we don't cover insects. I said ok, this tv is five months old. This insect could have been in there the whole time even when I purchsed it and simply fallen down into the middle of the screen over time. He told me they all go through quality checks and insisted that the bug was not in there which I argued against. I told him if the TV's are designed to not allow bugs into the screen then how can't this particular TV be a manufacturers defect? He had no answer of course except I am very sorry sir but we don't cover that, the bug was not in the screen when you purchased it. He told me he had never heard of this. I said google "Samsung, insect, tv" and you will hear of it. I think this is absolute BS.
I just wanted to let people know how piss poor Samsung's customer support is and don't bother calling if your very expensive TV's gets messed up by an insect (although I did read a few places that people had success getting it repaired, not sure how).
I will never buy another TV or product for that matter from Samsung. It's a shame that a billion dollar company with products I like could care less about the little man. But just wanted to let you all know again out there BUYER BEWARE.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic