A Facebook representative sent a statement to Engadget, which is reproduced in full below:
It’s natural that Facebook will come to this decision, really. With streaming quality on YouTube and Netflix having a hard cap, users will naturally flock to other services without one. Nevermind that the social media networks already have a massive user base. It also doesn’t help that there’s a pandemic going around. As a result, users will also be more likely to be at home, bored and active on social media. It’s also especially important for both Facebook and Instagram to limit the network strain on their services. Users also use them for communication with others, so it’s obviously a good idea to not overload the network with just video streaming. (Source: Engadget)