It appears you are using Kaltura as your media host, as such they have to aquire a certificate in order to use an ssl link. There is no reason other then company policy and laziness that they would not provide a simple http link instead of an https link, or they would get the proper certificate/s.
If they are linking to a 'sub host" then they are nothing more then an index for that other host, both sites would be required to a have proper certificates and include each other as cross domains..
Thats the layans issue of what you are encountering. The solution would be to rent a server and ost it yourself where you have complete control, or going with another hosting company that does things correctly.
As for youtube, the biggest problem i have with youtube is that you do not own your creation once you uplod it to youtube. yes, you retain 'ownership" but you extended them a forever license to use and profit from your content with zero compensation to it once you uploaded it to them. And if you make money from another media outlet they are entitled to a chunk of that money as well.
So if you write a movie and put it on Youtube, you just gave them all rights to that movie past futue and present. If a big time hollywood producer picks up your movie and wants to make it into a blockbuster series of movies, you just gave away a percentage of all future earnings related to the movie. Most of the time when this happens 9and it rarely does but has) The big time producer will negotiate a deal with google (youtube) to purchase back the rights in a single large sum dollar amount. But Youtube is under no legal obligation to release their rights.
I dislike youtube, did snce the day they stole my idea and started thier business.
Anyway, I average about 100$ month from Roku in ad revenue, not much considering the hosting costs, I get about the same from apple and Amazon, although Amazon is a pain in the arse cause I have to keep sending them proof of rights to use some of the material I publish and have to constently prove some of them are publicc domain. Between the 3 services i do a little more then break even. Maybe if I invested in advertising I'd do much better, but I like it small, lol.. This is just a hobby now as I am retired..